feat: support passing dynamic key-value pairs in helm-template step

[michaelasper]

implements #3753

have it working locally, will update/add tests

first time hacking on kargo internals, hopefully in the right direction

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 52.25%. Comparing base (6b49a88) to head (3c3b41e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3795      +/-   ##
==========================================
+ Coverage   52.24%   52.25%   +0.01%     
==========================================
  Files         309      309              
  Lines       27601    27609       +8     
==========================================
+ Hits        14420    14428       +8     
  Misses      12400    12400              
  Partials      781      781              

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[aarontams]

Thanks @michaelasper
I reviewed the PR, and it is very promising!
Hopefully, it will be approved by the Kargo team and included in the next release.