feat: Consumer Group can be configured

[programmer04]

What this PR does / why we need it:

In #4325 Consumer Group CRD and the boilerplate controller has been introduced. This PR continues that effort - applied Consumer Group will be configured in Kong Gateway. Validation webhook, adding Consumers, and scoping Plugins will be introduced in the next PRs.

Which issue this PR fixes:

This is a part of #3728 and closes #4358

Special notes for your reviewer:

The introduced integration test TestConsumerGroup will evolve in the future to cover all features of it e.g. adding Consumers to Consumer Group. Since Consumer Group doesn't do anything useful yet for now check directly in Gateway if it was created. Later it will be replaced with a proper testing scenario.

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• the CHANGELOG.md release notes have been updated to reflect any significant (and particularly user-facing) changes introduced by this PR

[codecov]

Codecov Report

Patch coverage: 39.3% and project coverage change: +4.7% 🎉

Comparison is base (4b4fcab) 61.6% compared to head (ac5cff6) 66.4%.

❗ Current head ac5cff6 differs from pull request most recent head a34634d. Consider uploading reports for the commit a34634d to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #4387     +/-   ##
=======================================
+ Coverage   61.6%   66.4%   +4.7%     
=======================================
  Files        159     158      -1     
  Lines      18680   18617     -63     
=======================================
+ Hits       11513   12362    +849     
+ Misses      6499    5494   -1005     
- Partials     668     761     +93     

Files Changed	Coverage Δ
internal/dataplane/deckgen/generate.go	49.7% <0.0%> (+5.2%)	⬆️
internal/dataplane/kongstate/kongstate.go	66.9% <6.6%> (-2.3%)	⬇️
internal/store/fake_store.go	39.6% <44.4%> (+0.1%)	⬆️
internal/store/store.go	59.3% <59.2%> (+0.8%)	⬆️
internal/dataplane/parser/parser.go	78.9% <100.0%> (+1.7%)	⬆️

... and 33 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.