Hide NGINX version

[sjberman]

Problem: As a user of NGF, I want the NGINX version of my installation of NGF hidden by default, so that I do not inadvertently expose which vulnerabilities my version of NGINX is vulnerable to.

Solution: Hide the nginx version that's included in responses.

Testing: Verified in the browser and using curl that the nginx version is not included.

Please focus on (optional): If you any specific areas where you would like reviewers to focus their attention or provide
specific feedback, add them here.

Closes #1507

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.

Hide NGINX version that is included in responses.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.76%. Comparing base (06a0090) to head (580b502).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2305   +/-   ##
=======================================
  Coverage   87.76%   87.76%           
=======================================
  Files          96       96           
  Lines        6793     6793           
  Branches       50       50           
=======================================
  Hits         5962     5962           
  Misses        774      774           
  Partials       57       57           

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