Add Rate-Limit xDS config server related control plane functionality

[renuka-fernando]

Related issue

Fix envoyproxy/go-control-plane#595

Proto files

PR: https://github.com/envoyproxy/ratelimit/pull/368

Description

To configure envoy rate limit service via xDS

[renuka-fernando]

@alecholmez could you please review this?

[renuka-fernando]

Hi @alecholmez,

What do you think is the best? Using ADS or having a separate RLS config service? I removed the RLS config service and commit https://github.com/envoyproxy/go-control-plane/pull/598/commits/d0a39a043e3bfaf89934ad6bf8eb5c2e35f2860a to this PR

[renuka-fernando]

Is there an xDS client for ADS that can be reused in the rate limit? So I do not want to implement an xDS client in the rate limit repo, just import from go-control-plane and use it.

[alecholmez]

Sorry for the slow response times! I'll begin to look into this.

I would actually like us to have RLS over ADS. That's the most common use case and if people begin to request that we supported a separated RLS service we can address that down the line.

[kkcmadhu]

please include this for java control plane too.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in 7 days if no further activity occurs. Please feel free to give a status update now, ping for review, or re-open when it's ready. Thank you for your contributions!

[renuka-fernando]

Hi @alecholmez,

Could you please run the failed build again and please review the PR? The issue with the build is fixed now: https://github.com/envoyproxy/go-control-plane/issues/625

[renuka-fernando]

@alecholmez, thank you very much for the support in getting this done.