* Allow for zero witness providers

* Verify provider duplicates, fix tests

* Add duplicate provider ID to the error

* Return error on attempt to remove last witness

* Verify duplicates when restoring from store

* rpc/client: remove the placeholder RunState type.

I added the RunState type in #6971 to disconnect clients from the service
plumbing, which they do not need. Now that we have more complete context
plumbing, the lifecycle of a client no longer depends on this type: It serves
as a carrier for a logger, and a Boolean flag for "running" status, neither of
which is used outside of tests.

Logging in particular is defaulted to a no-op logger in all production use.
Arguably we could just remove the logging calls, since they are never invoked
except in tests. To defer the question of whether we should do that or make the
logging go somewhere more productive, I've preserved the existing use here.

Remove use of the IsRunning method that was provided by the RunState, and use
the Start method and context to govern client lifecycle.

Remove the one test that exercised "unstarted" clients. I would like to remove
that method entirely, but that will require updating the constructors for all
the client types to plumb a context and possibly other options. I have deferred
that for now.

Responses are constructed from requests using MakeResponse, MakeError, and
MakeErrorf. This ensures the response is always paired with the correct ID,
makes cases where there is no ID more explicit at the usage site, and
consolidates the handling of error introspection across transports.

The logic for unpacking errors and assigning JSON-RPC response types was
previously duplicated in three places. Consolidate it in the types package for
the RPC subsystem.

* update test cases

- use the full key path to pass to the VerifyAbsence function

This pull request merges in the changes for implementing Proposer-based timestamps into `master`. The power was primarily being done in the `wb/proposer-based-timestamps` branch, with changes being merged into that branch during development. This pull request represents an amalgamation of the changes made into that development branch. All of the changes that were placed into that branch have been cleanly rebased on top of the latest `master`. The changes compile and the tests pass insofar as our tests in general pass.

### Note To Reviewers
 These changes have been extensively reviewed during development. There is not much new here. In the interest of making effective use of time, I would recommend against trying to perform a complete audit of the changes presented and instead examine for mistakes that may have occurred during the process of rebasing the changes. I gave the complete change set a first pass for any issues, but additional eyes would be very appreciated. 

In sum, this change set does the following:
closes #6942 
merges in #6849

There are no further uses of this package anywhere in Tendermint.
All the uses in the Cosmos SDK are for types that now work correctly with the
standard encoding/json package.

The main change here is to use encoding/json to encode and decode RPC 
parameters, rather than the custom tmjson package. This includes:

- Update the HTTP POST handler parameter handling.
- Add field tags to 64-bit integer types to get string encoding (to match amino/tmjson).
- Add marshalers to struct types that mention interfaces.
- Inject wrappers to decode interface arguments in RPC handlers.

*light: rpc /status returns status of light client ; code refactoring
 light: moved lightClientInfo into light.go, renamed String to ID
test/e2e: Return light client trusted height instead of SyncInfo trusted height
test/e2e/start.go: Not waiting for light client to catch up in tests. Removed querying of syncInfo in start if the node is a light node

* light: Removed call to primary /status. Added trustedPeriod to light info
* light/provider: added ID function to return IP of primary and witnesses
* light/provider/http/http_test: renamed String() to ID()

This commit changes the behaviour of the /unconfirmed_txs endpoint by replacing limit with a page and perPage parameter for pagination.
The test case for unconfirmed_txs have been accommodated to properly test this change and the documentation for the API as well.

The custom error types in the provider package did not propagate their wrapped
underlying reasons, making it difficult for the test to check that the correct
error was observed.

- Fix the custom errors to have a true underlying error (not just a string).
- Add Unwrap methods to support inspection by errors.Is.
- Update usage in a few places.
- Fix the test to check for acceptable variation.

Fixes #7609.

Define interfaces for the various methods a service may implement.  This is
basically just the set of things on Environment that are exported as RPCs, but
these are also implemented by the light proxy.

* internal/rpc: use NewRoutesMap to construct routes on service start
* light/proxy: use NewRoutesMap to construct RPC routes

We should not set cache-control headers on RPC responses. HTTP caching
interacts poorly with resources that are expected to change frequently, or
whose rate of change is unpredictable.

More subtly, all calls to the POST endpoint use the same URL, which means a
cacheable response from one call may actually "hide" an uncacheable response
from a subsequent one. This is less of a problem for the GET endpoints, but
that means the behaviour of RPCs varies depending on which HTTP method your
client happens to use. Websocket requests were already marked statically
uncacheable, adding yet a third combination.

To address this:

- Stop setting cache-control headers.
- Update the tests that were checking for those headers.
- Remove the flags to request cache-control.

Apart from affecting the HTTP response headers, this change does not modify the
behaviour of any of the RPC methods.

* Rename rpctypes.Context to CallInfo.

Add methods to attach and recover this value from a context.Context.

* Rework RPC method handlers to accept "real" contexts.

- Replace *rpctypes.Context arguments with context.Context.
- Update usage of RPC context fields to use CallInfo.

No API changes, merely changes the import path.

This continues the push of plumbing contexts through tendermint. I
attempted to find all goroutines in the production code (non-test) and
made sure that these threads would exit when their contexts were
canceled, and I believe this PR does that.

Co-authored-by: Callum Waters <cmwaters19@gmail.com>
Co-authored-by: M. J. Fromberger <fromberger@interchain.io>

Fixes #7098. The light client documentation moved to the spec repository.

I was not able to figure out what happened to light-client-protocol.md, it was removed in #5252 but no corresponding file exists in the spec repository. Since the spec also discusses the protocol, this change simply links to the spec and removes the non-functional reference.

Alternatively we could link to the top-level [light client doc](https://docs.tendermint.com/master/tendermint-core/light-client.html) if you think that's better.

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.

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.

The responses from node RPCs encode hash values as hexadecimal strings. This
behaviour is stipulated in our OpenAPI documentation. In some cases, however,
hashes received as JSON parameters were being decoded as byte buffers, as is
the convention for JSON.

This resulted in the confusing situation that a hash reported by one request
(e.g., broadcast_tx_commit) could not be passed as a parameter to another
(e.g., tx) via JSON, without translating the hex-encoded output hash into the
base64 encoding used by JSON for opaque bytes.

Fixes #6802.

EDIT: Updated, see [comment below]( https://github.com/tendermint/tendermint/pull/6785#issuecomment-897793175)

This change adds a sketch of the `Debug` mode. 

This change adds a `Debug` struct to the node package. This `Debug` struct is intended to be created and started by a command in the `cmd` directory. The `Debug` struct runs the RPC server on the data directories: both the state store and the block store.

This change required a good deal of refactoring. Namely, a new `rpc.go` file was added to the `node` package. This file encapsulates functions for starting RPC servers used by nodes. A potential additional change is to further factor this code into shared code _in_ the `rpc` package. 

Minor API tweaks were also made that seemed appropriate such as the mechanism for fetching routes from the `rpc/core` package.

Additional work is required to register the `Debug` service as a command in the `cmd` directory but I am looking for feedback on if this direction seems appropriate before diving much further.

closes: #5908

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

This pull request removes the homegrown mocks in `light/provider/mock` in favor of mockery mocks.

Adds a simple benchmark only mock to avoid the overhead of `reflection` that `mockery` incurs.

part of #5274