actionConfigGetter: allow custom mapping from object to rest.Config

[joelanford]

Fixes #316

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 79.59184% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 85.69%. Comparing base (08ab7fb) to head (5a44fe1).
Report is 13 commits behind head on main.

Files	Patch %	Lines
pkg/client/actionconfig.go	74.35%	7 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #317      +/-   ##
==========================================
+ Coverage   85.06%   85.69%   +0.62%     
==========================================
  Files          19       19              
  Lines        1346     1510     +164     
==========================================
+ Hits         1145     1294     +149     
- Misses        125      139      +14     
- Partials       76       77       +1     

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[porridge]

FTR, I cherry-picked this change to what stackrox operator uses and ran our e2e tests in a loop to see if this would provoke increased memory usage like it did before #198 but found no adverse effects.

With this change:

Without this change:

[varshaprasad96]

Looks good to me! Just one question.

[varshaprasad96]

/lgtm