[ci] Expose operator page to change internal-gateway rate limit

[daniel-goldstein]

What happened?

Currently, in order to change the rate limit in internal-gateway, one has to manually edit envoy.py and redeploy CI. This is non-standard, time intensive and can be accidentally reverted if CI merges a new commit to main. CI already regularly updates the envoy configuration internal-gateway uses to account for services in new namespaces, so making the rate limit configurable should be a simple CRUD task that would greatly ease operation of batch under high load.

One gotcha to keep in mind is that while we run CI as a control plane for our "dynamic cluster topology", it should still be possible to manually deploy internal-gateway in a standalone Batch cluster (see internal-gateway/Makefile), so envoy.py should still be runnable as a standalone script.

Version

0.2.128

Relevant log output

No response