This is another batch of things to cleanup in the legacy P2P system.

Addresses one of the concerns with #7041.

Provides a mechanism (via the RPC interface) to delete a single transaction, described by its hash, from the mempool. The method returns an error if the transaction cannot be found. Once the transaction is removed it remains in the cache and cannot be resubmitted until the cache is cleared or it expires from the cache.

This code hasn't been battle tested, and seems to have grown
increasingly flaky int tests. Given our general direction of reducing
queue complexity over the next couple of releases I think it makes
sense to remove it.

A few notes:

- this is not all the deletion that we can do, but this is the most
  "simple" case: it leaves in shims, and there's some trivial
  additional cleanup to the transport that can happen but that
  requires writing more code, and I wanted this to be easy to review
  above all else.
  
- This should land *after* we cut the branch for 0.35, but I'm
  anticipating that to happen soon, and I wanted to run this through
  CI.

The race occurred as a result of a goroutine launched by `processPeerUpdate` racing with the `OnStop` method. The `processPeerUpdates` goroutine deletes from the map as `OnStop` is reading from it. This change updates the `OnStop` method to wait for the peer updates channel to be done before closing the peers. It also copies the map contents to a new map so that it will not conflict with the view of the map that the goroutine created in `processPeerUpdate` sees.

This commit should be one of the first to land as part of the v0.36
cycle *after* cutting the 0.35 branch. 

The blocksync/v2 reactor was originally implemented as an experiement
to produce an implementation of the blockstack protocol that would be
easier to test and validate, but it was never appropriately
operationalized and this implementation was never fully debugged. When
the p2p layer was refactored as part of the 0.35 cycle, the v2
implementation was not refactored and it was left in the codebase but
not removed. This commit just removes all references to it.

This is intended to fix a test failure that occurs in the p2p state provider. The issue presents as the state provider timing out waiting for the consensus params response. 

The reason that this can occur is because the statesync reactor has the possibility of attempting to respond to the params request before the state provider is ready to read it. This results in the reactor hitting the `default` case seen here and then never sending on the channel. The stateprovider will then block waiting for a response and never receive one because the reactor opted not to send it.

When statesync is stopped during shutdown, it has the possibility of deadlocking. A dump of goroutines reveals that this is related to the peerUpdates channel not returning anything on its `Done()` channel when `OnStop` is called. As this is occuring, `processPeerUpdate` is attempting to acquire the reactor lock. It appears that this lock can never be acquired. I looked for the places where the lock may remain locked accidentally and cleaned them up in hopes to eradicate the issue. Dumps of the relevant goroutines may be found below. Note that the line numbers below are relative to the code in the `v0.35.0-rc1` tag.

```
goroutine 36 [chan receive]:
github.com/tendermint/tendermint/internal/statesync.(*Reactor).OnStop(0xc00058f200)
        github.com/tendermint/tendermint/internal/statesync/reactor.go:243 +0x117
github.com/tendermint/tendermint/libs/service.(*BaseService).Stop(0xc00058f200, 0x0, 0x0)
        github.com/tendermint/tendermint/libs/service/service.go:171 +0x323
github.com/tendermint/tendermint/node.(*nodeImpl).OnStop(0xc0001ea240)
        github.com/tendermint/tendermint/node/node.go:769 +0x132
github.com/tendermint/tendermint/libs/service.(*BaseService).Stop(0xc0001ea240, 0x0, 0x0)
        github.com/tendermint/tendermint/libs/service/service.go:171 +0x323
github.com/tendermint/tendermint/cmd/tendermint/commands.NewRunNodeCmd.func1.1()
        github.com/tendermint/tendermint/cmd/tendermint/commands/run_node.go:143 +0x62
github.com/tendermint/tendermint/libs/os.TrapSignal.func1(0xc000629500, 0x7fdb52f96358, 0xc0002b5030, 0xc00000daa0)
        github.com/tendermint/tendermint/libs/os/os.go:26 +0x102
created by github.com/tendermint/tendermint/libs/os.TrapSignal
        github.com/tendermint/tendermint/libs/os/os.go:22 +0xe6

goroutine 188 [semacquire]:
sync.runtime_SemacquireMutex(0xc00026b1cc, 0x0, 0x1)
        runtime/sema.go:71 +0x47
sync.(*Mutex).lockSlow(0xc00026b1c8)
        sync/mutex.go:138 +0x105
sync.(*Mutex).Lock(...)
        sync/mutex.go:81
sync.(*RWMutex).Lock(0xc00026b1c8)
        sync/rwmutex.go:111 +0x90
github.com/tendermint/tendermint/internal/statesync.(*Reactor).processPeerUpdate(0xc00026b080, 0xc000650008, 0x28, 0x124de90, 0x4)
        github.com/tendermint/tendermint/internal/statesync/reactor.go:849 +0x1a5
github.com/tendermint/tendermint/internal/statesync.(*Reactor).processPeerUpdates(0xc00026b080)
        github.com/tendermint/tendermint/internal/statesync/reactor.go:883 +0xab
created by github.com/tendermint/tendermint/internal/statesync.(*Reactor.OnStart
        github.com/tendermint/tendermint/internal/statesync/reactor.go:219 +0xcd)
```

The layout of struct fields means that interior fields may not be properly
aligned for 64-bit access.

Fixes #7000.

When shutting down blocksync, it is observed that the process can hang completely. A dump of running goroutines reveals that this is due to goroutines not listening on the correct shutdown signal. Namely, the `poolRoutine` goroutine does not wait on `pool.Quit`. The `poolRoutine` does not receive any other shutdown signal during `OnStop` becuase it must stop before the `r.closeCh` is closed. Currently the `poolRoutine` listens in the `closeCh` which will not close until the `poolRoutine` stops and calls `poolWG.Done()`.

This change also puts the `requestRoutine()` in the `OnStart` method to make it more visible since it does not rely on anything that is spawned in the `poolRoutine`.

```
goroutine 183 [semacquire]:
sync.runtime_Semacquire(0xc0000d3bd8)
        runtime/sema.go:56 +0x45
sync.(*WaitGroup).Wait(0xc0000d3bd0)
        sync/waitgroup.go:130 +0x65
github.com/tendermint/tendermint/internal/blocksync/v0.(*Reactor).OnStop(0xc0000d3a00)
        github.com/tendermint/tendermint/internal/blocksync/v0/reactor.go:193 +0x47
github.com/tendermint/tendermint/libs/service.(*BaseService).Stop(0xc0000d3a00, 0x0, 0x0)
        github.com/tendermint/tendermint/libs/service/service.go:171 +0x323
github.com/tendermint/tendermint/node.(*nodeImpl).OnStop(0xc00052c000)
        github.com/tendermint/tendermint/node/node.go:758 +0xc62
github.com/tendermint/tendermint/libs/service.(*BaseService).Stop(0xc00052c000, 0x0, 0x0)
        github.com/tendermint/tendermint/libs/service/service.go:171 +0x323
github.com/tendermint/tendermint/cmd/tendermint/commands.NewRunNodeCmd.func1.1()
        github.com/tendermint/tendermint/cmd/tendermint/commands/run_node.go:143 +0x62
github.com/tendermint/tendermint/libs/os.TrapSignal.func1(0xc000df6d20, 0x7f04a68da900, 0xc0004a8930, 0xc0005a72d8)
        github.com/tendermint/tendermint/libs/os/os.go:26 +0x102
created by github.com/tendermint/tendermint/libs/os.TrapSignal
        github.com/tendermint/tendermint/libs/os/os.go:22 +0xe6


goroutine 161 [select]:
github.com/tendermint/tendermint/internal/blocksync/v0.(*Reactor).poolRoutine(0xc0000d3a00, 0x0)
        github.com/tendermint/tendermint/internal/blocksync/v0/reactor.go:464 +0x2b3
created by github.com/tendermint/tendermint/internal/blocksync/v0.(*Reactor).OnStart
        github.com/tendermint/tendermint/internal/blocksync/v0/reactor.go:174 +0xf1

goroutine 162 [select]:
github.com/tendermint/tendermint/internal/blocksync/v0.(*Reactor).processBlockSyncCh(0xc0000d3a00)
        github.com/tendermint/tendermint/internal/blocksync/v0/reactor.go:310 +0x151
created by github.com/tendermint/tendermint/internal/blocksync/v0.(*Reactor).OnStart
        github.com/tendermint/tendermint/internal/blocksync/v0/reactor.go:177 +0x54

goroutine 163 [select]:
github.com/tendermint/tendermint/internal/blocksync/v0.(*Reactor).processPeerUpdates(0xc0000d3a00)
        github.com/tendermint/tendermint/internal/blocksync/v0/reactor.go:363 +0x12b
created by github.com/tendermint/tendermint/internal/blocksync/v0.(*Reactor).OnStart
        github.com/tendermint/tendermint/internal/blocksync/v0/reactor.go:178 +0x76
```

This test reliably gets hung up on network configuration, (which may
be a real issue,) but it's network setup is handcranked and we should
ensure that the test focuses on it's core assertions and doesn't fail for 
test architecture reasons.

Closes https://github.com/tendermint/tendermint/issues/7014

I've been noticing that there are a number of situations where the
statesync reactor blocks waiting for peers (or similar,) I've moved
things around to improve outcomes in local tests.

The code in the Tendermint repository makes heavy use of import aliasing.
This is made necessary by our extensive reuse of common base package names, and
by repetition of similar names across different subdirectories.

Unfortunately we have not been very consistent about which packages we alias in
various circumstances, and the aliases we use vary. In the spirit of the advice
in the style guide and https://github.com/golang/go/wiki/CodeReviewComments#imports,
his change makes an effort to clean up and normalize import aliasing.

This change makes no API or behavioral changes. It is a pure cleanup intended
o help make the code more readable to developers (including myself) trying to
understand what is being imported where.

Only unexported names have been modified, and the changes were generated and
applied mechanically with gofmt -r and comby, respecting the lexical and
syntactic rules of Go.  Even so, I did not fix every inconsistency. Where the
changes would be too disruptive, I left it alone.

The principles I followed in this cleanup are:

- Remove aliases that restate the package name.
- Remove aliases where the base package name is unambiguous.
- Move overly-terse abbreviations from the import to the usage site.
- Fix lexical issues (remove underscores, remove capitalization).
- Fix import groupings to more closely match the style guide.
- Group blank (side-effecting) imports and ensure they are commented.
- Add aliases to multiple imports with the same base package name.

We moved some files further down in the directory structure in #6964, which
caused the relative paths to the mockery wrapper to stop working.

There does not seem to be an obvious way to get the module root as a default
environment variable, so for now I just added the extra up-slashes.

This document attempts to capture and discuss some of the areas of Tendermint that seem to be cited as causing performance issue. I'm hoping to continue to gather feedback and input on this document to better understand what issues Tendermint performance may cause for our users. 

The overall goal of this document is to allow the maintainers and community to get a better sense of these issues and to be more capably able to discuss them and weight trade-offs about any proposed performance-focused changes. This document does not aim to propose any performance improvements. It does suggest useful places for benchmarks and places where additional metrics would be useful for diagnosing and further understanding Tendermint performance.

Please comment with areas where my reasoning seems off or with additional areas that Tendermint performance may be causing user pain.

* add information on upgrading to the new p2p library

* clarify p2p backwards compatibility

* reorder p2p queue list

* add demo for p2p selection

* fix spacing in upgrading

This is a little change just to make things more consistent ahead of
the 0.35 release.

Issues reported in Osmosis, where the message is extremely long. Also, there is absolutely no reason to log the message IMO. If we must, we can make the message log DEBUG.

Adds a simple property test to the `clist` package. This test uses the [rapid](https://github.com/flyingmutant/rapid) library and works by modeling the internal clist as a simple array.

Follow up from this mornings workshop with the Regen team.

This changes adds a failing test for issue #6660. It achieves this by adding a transaction, starting the `broadcastTxRoutine` in a goroutine and then adding another transaction to the mempool. The `broadcastTxRoutine` can receive the second inserted transaction before `insertTx` returns. In that case, `broadcastTxRoutine` will derefence a nil pointer when referencing the `gossipEl` and panic.

This change aims to keep versions of mockery consistent across developer laptops.

This change adds mockery to the `tools.go` file so that its version can be managed consistently in the `go.mod` file.

Additionally, this change temporarily disables adding mockery's version number to generated files. There is an outstanding issue against the mockery project related to the version string behavior when running from `go get`. I have created a pull request to fix this issue in the mockery project.
see: https://github.com/vektra/mockery/issues/397

Update those break statements inside case clauses that are intended to reach an
enclosing for loop, so that they correctly exit the loop.

The candidate files for this change were located using:

    % staticcheck -checks SA4011 ./... | cut -d: -f-2

This change is intended to preserve the intended semantics of the code, but
since the code as-written did not have its intended effect, some behaviour may
change. Specifically: Some loops may have run longer than they were supposed
to, prior to this change.

In one case I was not able to clearly determine the intended outcome. That case
has been commented but otherwise left as-written.

Fixes #6780.

This adds a test for closing the `pqueue` while the `pqueue` contains data that has not yet been dequeued.

This issue was found while debugging #6705 

This test will fail until @cmwaters fix for this condition is merged.

This change adds additional coverage to the `mConnConnection.TrySendMessage` code path. Adds test to ensure it returns `io.EOF` when closed.

Addresses: #6570

This changes adds an `MempoolError` field to the `ResponseCheckTx`. This will allow clients to understand that their transaction was rejected from the mempool despite passing the ABCI check. 

This change also updates the code to make use of early returns to prevent highly nested code blocks. Namely, it returns when the type assertion fails at the beginning of the method, instead of wrapping the entire method in a large if statement. This has a somewhat large effect on the diff as rendered by github.

addresses: #3546

closes #2498 
solves part of #3365

Note: difficult to test the event emit in SwitchToFastSync part, might need to change `stateSyncReactor` to an interface in the `nodeImpl` struct