1. Moved code for the GCP proxy to where the [] proxy code used to live.
3. Corrected reference to the GCP proxy location.
4. Misc changes to make ErrorProne and various tools happy.
+diekmann to LGTM terraform whitelist change.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=213630560
When a quota request is rejected, increment the metric counter by one.
Also makes both frontend and backend metrics singleton because all the fields they have a static.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=185146804
The quota handler terminates connections when quota is exceeded.
The next CL will add instrumentation for quota related metrics.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=185042675