feat: add flagd-proxy HA configuration

[xvzf]

This PR

• Add support for multi-replica flagd-proxy deployments

Related Issues

Fixes #609

Notes

Follow-up Tasks

How to test

Deploy with e.g. FLAGD_PROXY_REPLICA_COUNT=3

[codecov]

Codecov Report

Attention: Patch coverage is 83.58209% with 22 lines in your changes missing coverage. Please review.

Project coverage is 86.25%. Comparing base (499661e) to head (2f6f42c).
Report is 27 commits behind head on main.

Files with missing lines	Patch %	Lines
common/flagdproxy/flagdproxy.go	84.07%	12 Missing and 6 partials ⚠️
controllers/core/featureflagsource/controller.go	63.63%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #712      +/-   ##
==========================================
- Coverage   86.51%   86.25%   -0.26%     
==========================================
  Files          19       19              
  Lines        1587     1681      +94     
==========================================
+ Hits         1373     1450      +77     
- Misses        173      184      +11     
- Partials       41       47       +6     

Files with missing lines	Coverage Δ
common/utils/utils.go	100.00% <100.00%> (ø)
controllers/core/featureflagsource/controller.go	54.21% <63.63%> (+2.90%)	⬆️
common/flagdproxy/flagdproxy.go	87.90% <84.07%> (-0.80%)	⬇️

... and 1 file with indirect coverage changes

Flag	Coverage Δ
unit-tests	86.25% <83.58%> (-0.26%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

[beeme1mr]

Thanks for the PR! I'll look into the image scanning CI issue, which is unrelated to this change.

[thisthat]

Thank you @xvzf for the PR with some extra refactoring 🙌
I left only some minor comments. In particular, I am not 100% sure if we should retry continuously to reconcile on an unmanaged OFO resource or we should skip it. What's your opinion here?

[beeme1mr]

Hey @xvzf, could you please resolve any open threads that have been resolved? I'll rereview once you're ready. The change looks great so far. Thanks!

[xvzf]

Here we go @beeme1mr @thisthat - been off for a couple of days, sorry for the delay

[thisthat]

Thanks a lot for the contribution @xvzf 🙌