Warnings for unsupported Gateway and Routes fields

[tataruty]

Proposed changes

Problem:
As an NGF user,
I want clear feedback when I've specified a field that is unsupported by NGF,
So that I understand why certain features aren't working.
Routes should still be considered valid and configured, so we don't break existing users

Solution:
For all fields in various resources (Gateway, HTTPRoute, GRPCRoute, etc) that NGF does not yet support, add validation and error conditions if they are specified
Routes should still be considered valid and configured, so we don't break existing users

Testing: Unit tests
deploy:

Please focus on (optional):
for documentation:
nginx/documentation#1268

Closes #3784

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.

[codecov]

Codecov Report

❌ Patch coverage is 85.10638% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.73%. Comparing base (a4ff583) to head (631f83a).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/controller/state/conditions/conditions.go	0.00%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4036      +/-   ##
==========================================
- Coverage   86.74%   86.73%   -0.01%     
==========================================
  Files         128      128              
  Lines       16664    16758      +94     
  Branches       62       62              
==========================================
+ Hits        14455    14535      +80     
- Misses       2026     2039      +13     
- Partials      183      184       +1     

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