ENG-11111.

Added some metrics to be able to monitor TokenDistributor mechanism, similar to how our telemetry for errors works.

I deployed this on staging, and after going into Cloudwatch -> Metrics, I was able to see all the events.

We can also create a dashboard for this using multi-source metrics, like this:

I'll create a follow-up task for this (link), and another for configuring alarms if needed (link).

Depends on D15231

Tested both locally and on staging.

1. Test that all tokens are handled
2. Test tokens are reclaimed after timeout
3. Test graceful shutdown
4. Test connection, e.g., send a message in the Farcaster app and check in the logs that events are received

Separately, on staging, I tested logs and metrics