GenerateVirtualServer upstreams config refactor

[pdabelf5]

Proposed changes

Pull common code into one function

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

Attention: Patch coverage is 81.03448% with 11 lines in your changes missing coverage. Please review.

Project coverage is 52.36%. Comparing base (35c4794) to head (39014a0).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/configs/virtualserver.go	81.03%	9 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7264      +/-   ##
==========================================
+ Coverage   52.30%   52.36%   +0.05%     
==========================================
  Files          89       89              
  Lines       21363    21365       +2     
==========================================
+ Hits        11174    11187      +13     
+ Misses       9721     9712       -9     
+ Partials      468      466       -2     

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