Check for deprecated/unknown environment variables

[Akshay2191]

Implemented a function to validate the environment variables passed are part of the new v3 allowed variables if not it should throw a warning message.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• I have run make install-tools and have attached any dependency changes to this pull request
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• If applicable, I have updated any relevant documentation (README.md)
• If applicable, I have tested my cross-platform changes on Ubuntu 22, Redhat 8, SUSE 15 and FreeBSD 13

[codecov]

Codecov Report

❌ Patch coverage is 90.47619% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.24%. Comparing base (383ce95) to head (71c2fdd).
⚠️ Report is 20 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/config/config.go	90.47%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1342      +/-   ##
==========================================
+ Coverage   84.88%   86.24%   +1.35%     
==========================================
  Files         100      102       +2     
  Lines       14520    12531    -1989     
==========================================
- Hits        12325    10807    -1518     
+ Misses       1734     1248     -486     
- Partials      461      476      +15     

Files with missing lines	Coverage Δ
internal/config/config.go	87.01% <90.47%> (+1.43%)	⬆️

... and 99 files with indirect coverage changes

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