Internal: Set image projects via configs

[Subbarker]

Description

This is a clean start from #1643

Right now we interpret image names passed in from configs to determine what project they come from, and where they are an "Image" or an "Image Family". This logic has grown in complexity over time and most importantly, requires changes to our testing logic whenever a new corner case shows up.

This PR implements storing project names alongside the image/family names with test configs in a way that is simple to manage for future tests. We are calling these strings "Image Specs"

E.g.:

Image Family / Project: <project>:<family>

Specific Image / Project: <project>=<image>

Related issue

b/330177642

How has this been tested?

Checklist:

• Unit tests
  • Unit tests do not apply.
  • Unit tests have been added/modified and passed for this PR.
• Integration tests
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  • Integration tests have been added/modified and passed for this PR.
• Documentation
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  • This PR introduces user visible changes and the corresponding documentation change has been made.
• Minor version bump
  • This PR introduces no new features.
  • This PR introduces new features, and there is a separate PR to bump the minor version since the last release already.
  • This PR bumps the version.