feat: support set value file for render

[ericzzzzzzz]

Fixes: #8594

Description

• add --set-value-flag to skaffold render command for users to provide a .env format key-value pair file to set their manifests templated fields.
• move ParseEnvVariablesFromFile method from verify util to skaffold pkg util as this can be a utility func across skaffold project.

Test Plan

• integration tests.

[codecov]

Codecov Report

Merging #8647 (edb086e) into main (290280e) will decrease coverage by 6.33%.
The diff coverage is 54.47%.

@@            Coverage Diff             @@
##             main    #8647      +/-   ##
==========================================
- Coverage   70.48%   64.15%   -6.33%     
==========================================
  Files         515      614      +99     
  Lines       23150    30808    +7658     
==========================================
+ Hits        16317    19766    +3449     
- Misses       5776     9560    +3784     
- Partials     1057     1482     +425     

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 394 files with indirect coverage changes

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[aaron-prindle]

LGTM!