Add support for chartRef in a HelmRelease

[allenporter]

Add support for parsing an OCIRepository https://fluxcd.io/flux/components/helm/helmreleases/#chart-reference

Obsoletes #709

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 80.55556% with 7 lines in your changes missing coverage. Please review.

Project coverage is 93.21%. Comparing base (fa82f5a) to head (003678b).

Files	Patch %	Lines
flux_local/manifest.py	73.33%	4 Missing ⚠️
flux_local/helm.py	85.71%	2 Missing ⚠️
flux_local/tool/visitor.py	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #769      +/-   ##
==========================================
+ Coverage   93.15%   93.21%   +0.06%     
==========================================
  Files          20       20              
  Lines        2207     2227      +20     
==========================================
+ Hits         2056     2076      +20     
  Misses        151      151              

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