Infra Update v4: Support spack.repos, Add Tiered Common Configuration Via spack.include

[CodeGat]

Closes #19

Note

This PR incorporates major build-ci changes into this CR, due to the deprecation of inputs.*-spack-packages-ref and inputs.spack-manifest-data-path

Background

More info and motivations in the linked issue, but essentially:

• Deprecating inputs.*-spack-packages-ref in favor of in-manfiest spack.repos section, like MDRs. By default, it will use the latest api-v2 for access-spack-packages, and the latest access/v1.1 for builtin spack packages, but you're free to add repos sections as needed. If you need the exact commit for either, it is in the artifact for that particular run.
• Deprecating inputs.spack-manifest-data-path in favor of tiered configuration via spack.include.
  • This may mean that common configuration across all manifests is moved to .github/build-ci/config/packages.yaml rather than in the datafile data/standard.json, which is being deprecated.

Note

Note the copilot co-author in the commit message - after a few manual updates for other CRs, I attempted to generalise the instructions for the other repos so it could be done quicker (this stuff usually takes me a couple days). But do note that I checked the changes with my human-eyes before committing :D

The PR

• Update the workflow entrypoints, as usual!
• Remove any inputs.*-spack-packages-refs and transplant them into manifests spack.repos sections
• Remove any inputs.spack-manifest-data-path and replace that with spack.include entries, either from Add top-level spack.includes default access-spack-packages#484 or a CR-level manifest to include.

Testing

See below!