I believe it was the case that blocksync was not consistently enabled in master, and this makes makes it the default in the master tests.

This change removes the partial gRPC interface to the RPC service, which was
deprecated in resolution of #6718.

Details:
- rpc: Remove the client and server interfaces and proto definitions.
- Remove the gRPC settings from the config library.
- Remove gRPC setup for the RPC service in the node startup.
- Fix various test helpers to remove gRPC bits.
- Remove the --rpc.grpc-laddr flag from the CLI.

Note that to satisfy the protobuf interface check, this change also includes a
temporary edit to buf.yaml, that I will revert after this is merged.

It seems weird in retrospect that we allow networks to contain
applications that use different ABCI protocols.

This is mostly just reading through the output of uparam, after
noticing that there were a few places where we were ignoring some arguments.

This tweaks the connectivity of test configurations, in hopes that more will be viable.

Additionally reduces the prevalence of testing the legacy mempool.

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

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.

This PR tackles the case of using the e2e application in a long lived testnet. The application continually saves snapshots (usually every 100 blocks) which after a while bloats the size of the application. This PR prunes older snapshots so that only the most recent 10 snapshots remain.

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.

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.

75% of the failures in the last run all ran with the 10kb
transactions. I'd like to dial it back and see if things improve more.

This reduces this situation where a node will get stuck block syncing,
which seemed to happen a lot in last nights run.

I observed a couple of problems with the generator in some recent tests: 

- there were a couple of hybrid test cases which did not have any
  legacy nodes (randomness and all.) I change the probability to
  produce more reliable results.

- added options to the generation to be able to add a max (to
  compliment the earlier min) number of nodes for local testing. 

- added an option to support reversing the sort order so "more
  complex" networks were first, as well as tweaked some of the point
  values. 

- this refactored the generators cli parsing to be a bit more clear.

In the last run, there were two problems at the RPC layer returned
from light nodes' RPC end points. I think exercising the light client
proxy RPC system is something that can/should be done via unit
testing, and that likely these errors are (in production) transient
and (in CI) very likely to fail for test environment issues.

I believe this assertion is likely redundant given that we're checking the block apphash.

If the e2e tests error, they leave all of the e2e state around including containers and networks etc. 
We should clean this up when the tests shuts down, even if it exits in error.

This should address last night's failure. We've taken the perspective
of "the load generator shouldn't cause tests to fail" in recent
days/weeks, and I think this is just a next step along that line. The
e2e tests shouldn't test performance. 

I included some comments indicating the ways that this isn't ideal (it
is perhaps not), and I think that if test networks could make
assertions about the required rate, that might be a cool future
improvement (and good, perhaps, for system benchmarking.)

I think the `Sync` check covers our primary use case, and perhaps we
can turn this back on in the future after some kind of event-system
rewrite, or RPC rewrite that will avoid the serverside timeout.

These are mostly the timeouts that I think we're still hitting in CI. 

At this point, the tests (on master) pass on my local machine (which is quite beefy) so I think this is just the first in (perhaps?) a sequence of changes that attempt to change timeouts and load patterns so that the tests pass in CI more reliably.

The previous implemention of hybrid set testing, which was entirely my
own creation, was a bit peculiar, and I think this probably clears thins up.

The previous implementation had far fewer legacy nodes in hybrid
networks, *and* also for some reason that I can't quite explain,
caused a test case to fail.

The 0.35 release cycle renamed the 'fastsync' functionality to 'blocksync'. This change brings the configuration parameters in line with that change. Namely, it updates the configuration file `[fastsync]` field to be `[blocksync]` and changes the command line flag and config file parameters `--fast-sync` and `fast-sync` to `--enable-block-sync` and `enable-block-sync` respectively.

Error messages were added to help users encountering these changes be able to quickly make the needed update to their files/scripts.

When using the old command line argument for fast-sync, the following is printed

```
./build/tendermint start --proxy-app=kvstore --consensus.create-empty-blocks=false --fast-sync=false
ERROR: invalid argument "false" for "--fast-sync" flag: --fast-sync has been deprecated, please use --enable-block-sync
```

When using one of the old config file parameters, the following is printed:
```
./build/tendermint start --proxy-app=kvstore --consensus.create-empty-blocks=false
ERROR: error in config file: a configuration parameter named 'fast-sync' was found in the configuration file. The 'fast-sync' parameter has been renamed to 'enable-block-sync', please update the 'fast-sync' field in your configuration file to 'enable-block-sync'
```