Allow configuration of NGINX Plus API access

[bjee19]

Allow configuration of NGINX Plus API access.

Problem: We want the ability to configure access to the NGINX Plus dashboard.

Solution: Add a field AllowedAddresses in the NginxProxy API to allow the user to configure access to the NGINX Plus dashboard.

Testing: Unit tests. Manually configured an NginxProxy resource, set up a Kind cluster with a Nodeport following our Get started guide, and confirmed that I could access the dashboard without needing to port-forward. Verified nginx plus template code is present when running on nginx plus and not present when running on nginx oss.

Closes #2716

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

Release notes

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please add a brief note that summarizes the change.

Allow configuration of NGINX Plus API access. 

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.06%. Comparing base (7a08f11) to head (b538622).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3066      +/-   ##
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+ Coverage   90.00%   90.06%   +0.05%     
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  Files         111      112       +1     
  Lines       11501    11570      +69     
  Branches       50       50              
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+ Hits        10351    10420      +69     
  Misses       1089     1089              
  Partials       61       61              

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[sjberman]

The values.yaml helm file should also be updated with the schema for this field. We'll also want to update the NGINX Dashboard document to mention that this value can be changed to allow access from different sources. A brief overview on how to set it up at install time or updating at runtime in the NginxProxy resource can be mentioned, with a link to the data plane configuration doc for more details.

[bjee19]

Realized I hadn't added any checks to NOT generate the nginx plus template code when running on oss. Added those checks by not populating the NginxPlus Configuration resource if we are running not in plus. Manually verified that the nginx plus template code is not present when running on oss, and still is present when running on plus.

Cool that this got caught in our automated Helm chart tests.

[salonichf5]

looks good to me