chore: Adding init container support for the Controller in Helm

[sbyrne13]

There is currently no capability to add custom init container code into the controller. This is particularly useful for things like adding a binary or tool that is necessary for cloud compatibility.

Also adding volume and volume mount support too so that we can share installed binaries to the controller.

Some background here - https://github.com/akuity/kargo/issues/3750

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 53.21%. Comparing base (1a504ad) to head (d149c38). Report is 1 commits behind head on main.

Additional details and impacted files

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##             main    #3879   +/-   ##
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  Coverage   53.21%   53.21%           
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  Files         312      312           
  Lines       28363    28363           
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  Hits        15094    15094           
  Misses      12478    12478           
  Partials      791      791           

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[krancour]

@sbyrne13 codegen needs to be run after modifications to values.yaml. It's how the chart's readme gets updated based on metadata in that file.

[sbyrne-teck]

Ah okay - thanks @krancour - done!

[krancour]

This LGTM, but requesting @hiddeco to voice any concerns if he has any.

fwiw, I momentarily contemplated whether this capability should be added to all the components, but I think the controller is the only one where it is likely needed, so I'm ok with doing just the one.

[sbyrne13]

@krancour - have updated this PR to also include volumes and volumeMounts after some more testing. Please re-review when you have some time. Thanks