feat(httproute): add ReferenceGrant watch

[pmalek]

What this PR does / why we need it:

This PR adds a watch for ReferenceGrant in HTTPRouteController.

With this change when a ReferenceGrant is deleted, the HTTPRoute gets its status update with a condition: type: ResolvedRefs, reason: RefNotPermitted and status set to "False".

Which issue this PR fixes:

Related: #3289

Apart from the above this will also make us pass this conformance test (yet to merged): kubernetes-sigs/gateway-api#1853

[codecov]

Codecov Report

Patch coverage: 71.2% and project coverage change: +58.9 🎉

Comparison is base (6b00bfa) 0.0% compared to head (3fd408d) 58.9%.

❗ Current head 3fd408d differs from pull request most recent head 1fccf4d. Consider uploading reports for the commit 1fccf4d to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           main   #3759      +/-   ##
=======================================
+ Coverage      0   58.9%   +58.9%     
=======================================
  Files         0     134     +134     
  Lines         0   15751   +15751     
=======================================
+ Hits          0    9291    +9291     
- Misses        0    5825    +5825     
- Partials      0     635     +635     

Impacted Files	Coverage Δ
...ternal/controllers/gateway/httproute_controller.go	57.2% <61.2%> (ø)
internal/controllers/gateway/gateway_utils.go	44.1% <100.0%> (ø)
internal/controllers/gateway/route_utils.go	75.0% <100.0%> (ø)
internal/util/builder/httpbackendref.go	76.4% <100.0%> (ø)

... and 130 files with indirect coverage changes

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[pmalek]

Actually let me add a test for that

[rainest]

My own merge contains a minor conflict fix in CHANGELOG.md. My kingdom for some sort of automation around that to just say "always accept both for this file", but whatever. Re-approving based on the previous approval.

[github-actions]

The backport to release/2.9.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-release/2.9.x release/2.9.x
# Navigate to the new working tree
cd .worktrees/backport-release/2.9.x
# Create a new branch
git switch --create backport-3759-to-release/2.9.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 d11292b10fd5366ae5f6b4e3083e2b05112d6d00
# Push it to GitHub
git push --set-upstream origin backport-3759-to-release/2.9.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/2.9.x

Then, create a pull request where the base branch is release/2.9.x and the compare/head branch is backport-3759-to-release/2.9.x.