* Add log traces to Nomulus service on GKE
Add request-scope log traces to Nomulus on GKE which, unlike
AppEngine and Cloud Run etc, does not generate traces for hosted
applications. This change only affects the GKE image. It does not affect
the AppEngine services.
Log traces are added to Nomulus-generated logs in request-processing
threads. Forked threads are not covered yet. The single relevant use
case (TimeLimiter) will be addressed in a followup PR.
The main change is in the logging configuration:
* Use gcp-cloud-logging's LoggingHandler
* Add gcp-cloud-logging's TraceLoggingEnhancer to the handler.
* Set a thread-local trace id through the TraceLoggingEnhancer in
ServletBase on request's entry and clear it on completion.
Also removed an unused class (`RequestLogId`).
* CR
* CR
