* 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.

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

This package is not used in the tendermint repository since 31e7cdee.

Note that this is not the same package as rpc/client/mock (N.B. singular) which
is still used in some tests.

A search of GitHub turns up only 11 uses, all of which are in clones of the
tendermint repo at old commits..

* rpc: Strip down the base RPC client interface.

Prior to this change, the RPC client interface requires implementing the entire
Service interface, but most of the methods of Service are not needed by the
concrete clients. Dissociate the Client interface from the Service interface.

- Extract only those methods of Service that are necessary to make the existing
  clients work.

- Update the clients to combine Start/Onstart and Stop/OnStop. This does not
  change what the clients do to start or stop. Only the websocket clients make
  use of this functionality anyway.

  The websocket implementation uses some plumbing from the BaseService helper.
  We should be able to excising that entirely, but the current interface
  dependencies among the clients would require a much larger change, and one
  that leaks into other (non-RPC) packages.

  As a less-invasive intermediate step, preserve the existing client behaviour
  (and tests) by extracting the necessary subset of the BaseService
  functionality to an analogous RunState helper for clients. I plan to obsolete
  that type in a future PR, but for now this makes a useful waypoint.

Related:
- Clean up client implementations.
- Update mocks.

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.

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

There are many `//go:generate mockery` lines in the source code.
This change adds a make target to invoke these mock generations.
This change also invokes the mock invocations and adds the resulting mocks to the repo.

Related to #5274

Closes #5106