Add OpenTelemetry support

[haywoodsh]

Proposed changes

Add otel support for NGINX Ingress Controller OSS and Plus
Added config map keys:

  otel-exporter-endpoint: "[(http|https)://]host:port" # Required
  otel-exporter-header-name: "name" # Optional
  otel-exporter-header-value: "value" # Optional
  otel-service-name: "unknown_service:nginx" # Optional
  otel-trace-in-http: "false" # Optional, enables otel tracing at the http context

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 52.47%. Comparing base (2f0cb58) to head (22359ed).
Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7642      +/-   ##
==========================================
+ Coverage   52.29%   52.47%   +0.18%     
==========================================
  Files          90       90              
  Lines       21472    21549      +77     
==========================================
+ Hits        11228    11308      +80     
+ Misses       9774     9772       -2     
+ Partials      470      469       -1     

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[github-actions]

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