Adding test-only-stacks option to build a subset of stacks

[pacostas]

Summary

This PR:

• introduces a new flag/option called --test-only-stacks on the test.sh stacks's script (stacks/scripts/test.sh)
• Refactors the test.sh script based on the images.json rationale, to reduce duplicate code.
• Does not change any of the default behavior of the test.sh script as is currently being used from all the stacks.
• It has been tested against all the jammy-*-stack repos

Use Cases

Due to the stacks that work with the extension, might end up having to support 30 or more stacks (currently is eight), the build process, before running the acceptance tests, might end up being quite long (over an hour). By having conditionally selecting which stacks to build, we enable:

• Parallelization on the Github workflows and therefore faster builds testing and releases, as we can conditionally specify with the new option/flag, a subset of the stacks to build and test on each github action.
• Faster local development, as usually the development happens only on one stack e.g. nodejs stack and therefore we can avoid to build/test all the stacks locally by specifying with the --test-only-stacks option the stacks to build.

Checklist

• [x] I have viewed, signed, and submitted the Contributor License Agreement.
• [ ] I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• [x] I have added an integration test, if necessary.
• [x] I have reviewed the styleguide for guidance on my code quality.
• [x] I'm happy with the commit history on this PR (I have rebased/squashed as needed).

[pacostas]

Related PR https://github.com/paketo-community/ubi-base-stack/pull/98

[pacostas]

@ForestEckhardt Hello!! Could you review this PR when possible?