kvserver: stop using internal executor for rangelog

[ajwerner]

Is your feature request related to a problem? Please describe.
The rangelog table is written as part of the change replicas protocol. It can be useful for debugging. The implementation currently leverages the internal executor. In fact, it's the only use of the internal executor by kvserver at this point (AFAICT). It is problematic because we'd like the system database to be more like a regular database in terms of mutability. Today we cannot use leasing infrastructure for certain system tables because they are used by the internal executor which in turn is used by kvserver which starts up before that other infrastructure.

Describe the solution you'd like

We can inject a much narrower interface into kvserver for writing eventlog entries and we can implement it using KV client APIs and lower-level sql encodings. In this way, we'll remove the bootstrapping dependency on sql-layer services.

Describe alternatives you've considered
We could stop writing rangelogs synchronously altogether, and we may, but either way we should break this dependency.

Additional context

This will resolve #35293.

Epic: CRDB-18596

Jira issue: CRDB-20156