Update main docs to 4.0.0

[pdabelf5]

Proposed changes

• Bring main docs in line with release 4.0.0 docs
• prepare for release 4.1.0

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

[github-actions]

✅ Deploy Preview will be available once build job completes!

Name	Link
😎 Deploy Preview	https://frontdoor-test-docs.nginx.com/previews/nginx-ingress-controller/7027/

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[vepatel]

seems helm snapshots needs to be updated as well

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 52.73%. Comparing base (c4c6114) to head (6c365b3).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7027      +/-   ##
==========================================
- Coverage   52.74%   52.73%   -0.01%     
==========================================
  Files          89       89              
  Lines       20824    20824              
==========================================
- Hits        10983    10981       -2     
- Misses       9387     9389       +2     
  Partials      454      454              

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