feat: custom actions interfaces and actions runner implementation

[renzodavid9]

Fixes: #8522

Description
This PR adds the set of interfaces and types used by the Custom Actions, and implements the ActionsRunner in charge of executing a custom action according to the configuration.

[codecov]

Codecov Report

Merging #8563 (46f45c6) into main (290280e) will decrease coverage by 6.39%.
The diff coverage is 54.47%.

@@            Coverage Diff             @@
##             main    #8563      +/-   ##
==========================================
- Coverage   70.48%   64.09%   -6.39%     
==========================================
  Files         515      617     +102     
  Lines       23150    30904    +7754     
==========================================
+ Hits        16317    19808    +3491     
- Misses       5776     9608    +3832     
- Partials     1057     1488     +431     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/completion.go	13.04% <0.00%> (-1.25%)	⬇️
cmd/skaffold/app/cmd/config/list.go	65.21% <ø> (ø)
cmd/skaffold/app/cmd/config/set.go	88.72% <ø> (ø)
cmd/skaffold/app/cmd/config/util.go	54.28% <ø> (ø)
cmd/skaffold/app/cmd/credits.go	100.00% <ø> (ø)
cmd/skaffold/app/cmd/credits/export.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/deploy.go	40.90% <0.00%> (-12.94%)	⬇️
cmd/skaffold/app/cmd/generate_pipeline.go	60.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_modules.go	65.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_profiles.go	66.66% <ø> (ø)
... and 39 more

... and 396 files with indirect coverage changes

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[gsquared94]

lgtm