Add crossplane framework for testing

[sjberman]

Problem: We want a way to verify nginx configuration reliably in our tests. This is especially useful when introducing new policies, without the desire for testing nginx functionality directly.

Solution: Added a framework for getting the nginx config and passing through crossplane into a structured JSON format for easier parsing.

Because we now use a local container for crossplane in our functional tests, we'll only support running these tests in a kind cluster.

Closes #2014

Checklist

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• 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

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[github-actions]

✅ All required contributors have signed the F5 CLA for this PR. Thank you!
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[sjberman]

I have hereby read the F5 CLA and agree to its terms

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.20%. Comparing base (3af2393) to head (dbcd3d2).
Report is 1 commits behind head on main.

Additional details and impacted files

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##             main    #2522   +/-   ##
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  Coverage   89.20%   89.20%           
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  Files         100      100           
  Lines        7642     7642           
  Branches       50       50           
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  Hits         6817     6817           
  Misses        768      768           
  Partials       57       57           

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[kate-osborn]

This is awesome 😎

[kate-osborn]

🚀