Reconcile multi arch support for push-image workflow

[pacostas]

Summary

This PR reconciles the implementation of push-image workflow for a single architecture with the multi-arch one that currently exists on jammy-tiny-stack.

• It does not change any of the current functionality of the stacks while pushing to the registry. It only extends the current functionality to support pushing multiarch images to the registry.

In addition to the changes on push-image.yml workflow, this PR introduces an extra script called publish.sh, which is able to push multiple architectures to the registry and not only a single one. The publish.sh script is based on the multi-arch implementation script that exists on jammy-tiny-stack https://github.com/paketo-buildpacks/jammy-tiny-stack/blob/main/scripts/publish.sh. In addition, extra functionality to the publish.sh script has been added to push one image per time instead of two (build and run images = stack), as jam now supports the publish-image argument. This enables faster push to image registries (in push-image workflow) due to job parallelization, less code on the push-image workflow as the same action is used for the build and the run image, a more generic approach to support ubi scenarios where the build image is not used/pushed in most of the stacks.

This PR has been tested to push the images properly to the registries. Test results :

• ubi-base-stack: https://github.com/pacostas/ubi-base-stack/actions/runs/11216366589
• jammy-tiny-stack: https://github.com/pacostas/jammy-tiny-stack/actions/runs/11218960285
• jammy-base-stack: https://github.com/pacostas/jammy-base-stack/actions/runs/11343601624

Use Cases

• Multi and single architecture support for the push-image workflow, without breaking the existing functionality.

Checklist

• 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)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).

[pacostas]

@ForestEckhardt