Push the base image after it's creation

[dannystaple]

The npm stage of the docker base stage can take some time. Time for other operations could be saved by having this base stored as a docker image in github.

Can a workflow store the result of the base image build? We will address pulling this in a later ticket, but for now let's just make it available.

I'm thinking that the following would be appropriate in on_call_build_site:

• Use the base image name ghcr.io/orionrobots/orionrobots-site.base.
• An input push tag - this would be a version/tag for after the colon.
• This workflow should always build the image - it will be in use for the following stages anyway. Do this before the named "build the site with docker compose" stage.
• If input push tag is set, push the base image using the specified tag. Push only after the other build stages are completed, such that they can gate the pushing - failed builds should not push an image.

Then the following workflows would be adjusted to modify it:

• .github/workflows/on_push_to_master_test_and_deploy.yaml would set the push tag to latest.
• .github/workflows/on_pr_test.yaml - this is a little trickier.
  • Use tj_actions changed files (with a sha version reference so it is somewhat protected against supply chain compromises) to verify if the following have changed in the pr:
    • the Dockerfile
    • packages.json/packages.lock
    • The on_call_build_site workflow
    • The on pr test workflow
  • If it has changed, provide a push tag of the pr number. Otherwise, do not set the parameter.

Do not attempt to add code to pull/make use of this artifact just yet - that will be addressed in a later ticket.

Acceptance criteria

• All modified files follow the editorconfig standards (pre-commit should help)
• The on_call_build_site workflow should build a base image.
• The on call build site should only push the image when other build stages have completed.
• PR conditions should only expect to push the image when relevant files changed.
• The push to master job should call it with the tag latest
• This PR would have created an appropriately tagged base docker image package.