feat(gwapi): setup controllers dynamically when required CRDs get installed

[czeslavo]

What this PR does / why we need it:

Adds a crds.DynamicController that ensures that RequiredCRDs are installed in the cluster and only then sets up all of its Controllers that depend on them. In case the CRDs are not installed at start-up time, DynamicController will set up a watch for CustomResourceDefinition and will dynamically set up its Controllers once it detects that all RequiredCRDs are already in place.

It's used for both the beta and alpha parts of the Gateway API.

Which issue this PR fixes:

Part of #3029.

Special notes for your reviewer:

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: 70.6% and project coverage change: -0.5 ⚠️

Comparison is base (8ce0421) 59.9% compared to head (2978bc1) 59.4%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3996     +/-   ##
=======================================
- Coverage   59.9%   59.4%   -0.5%     
=======================================
  Files        148     149      +1     
  Lines      16290   16399    +109     
=======================================
- Hits        9759    9753      -6     
- Misses      5898    6009    +111     
- Partials     633     637      +4     

Impacted Files	Coverage Δ
internal/manager/scheme/scheme.go	22.5% <0.0%> (-2.5%)	⬇️
internal/controllers/crds/dynamic_controller.go	17.4% <17.4%> (ø)
internal/controllers/gateway/gateway_controller.go	12.6% <87.5%> (+1.2%)	⬆️
...ternal/controllers/gateway/httproute_controller.go	48.3% <90.0%> (-9.0%)	⬇️
internal/manager/controllerdef.go	98.8% <100.0%> (+<0.1%)	⬆️

... and 3 files with indirect coverage changes

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[pmalek]

I believe we should add a changelog entry for this. WDYT @czeslavo ?

[pmalek]

👍 🚢