RFC 624: (M1) Re-build PoC recognizers

Created by: efritz

Implements a portion of RFC 624: Configurable auto-indexing recognizers.

Re-implement the existing recognizer behaviors in Lua using the exact interfaces that are declared today. Create a version of a Lua sandbox introduced in #33042 (closed) that exposes the gitserver client methods to the script. Ensure that the current recognizer unit tests pass against this new sandbox executor.

This issue does not yet make the sandbox accessible outside of tests.