Add SupportedFeatures to GatewayClassStatus

[ciarams87]

Proposed changes

Problem: As part of Gateway API release 1.4, the field supportedFeatures in GatewayClass spec is being moved to standard. We don't currently support this.

Solution: Add SupportedFeatures to GatewayClassStatus

Testing: Output of describe on GatewayClass (with experimental enabled - TLSRoute is not present in the list otherwise) :

k describe gatewayclasses.gateway.networking.k8s.io nginx
Name:         nginx
<....>
  Supported Features:
    Name:  BackendTLSPolicy
    Name:  GRPCRoute
    Name:  Gateway
    Name:  GatewayAddressEmpty
    Name:  GatewayHTTPListenerIsolation
    Name:  GatewayInfrastructurePropagation
    Name:  GatewayPort8080
    Name:  GatewayStaticAddresses
    Name:  HTTPRoute
    Name:  HTTPRouteBackendProtocolWebSocket
    Name:  HTTPRouteDestinationPortMatching
    Name:  HTTPRouteHostRewrite
    Name:  HTTPRouteMethodMatching
    Name:  HTTPRouteParentRefPort
    Name:  HTTPRoutePathRedirect
    Name:  HTTPRoutePathRewrite
    Name:  HTTPRoutePortRedirect
    Name:  HTTPRouteQueryParamMatching
    Name:  HTTPRouteRequestMirror
    Name:  HTTPRouteRequestMultipleMirrors
    Name:  HTTPRouteRequestPercentageMirror
    Name:  HTTPRouteResponseHeaderModification
    Name:  HTTPRouteSchemeRedirect
    Name:  ReferenceGrant
    Name:  TLSRoute
Events:    <none>

Confirmed that the same conformance tests run as when we had the supported-features flag configured

Please focus on (optional): If you any specific areas where you would like reviewers to focus their attention or provide
specific feedback, add them here.

Closes #3943

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

Add SupportedFeatures to GatewayClassStatus

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.16%. Comparing base (aa0f45c) to head (ed6a80a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4236      +/-   ##
==========================================
- Coverage   86.17%   86.16%   -0.01%     
==========================================
  Files         131      132       +1     
  Lines       14217    14273      +56     
  Branches       35       35              
==========================================
+ Hits        12252    12299      +47     
- Misses       1763     1769       +6     
- Partials      202      205       +3     

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