Speed up test suite with Docker image

[davidmerfield]

Main goal is to reduce the time it takes to run the CI tests
One possible idea (this PR) is to generate a docker image built with the appropriate tools installed that we can re-use when only the application code changes. Otherwise we run a script to build a new image.

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• Re-add existing workflows
• Scope GH actions to changes in relevant directories? https://github.community/t/run-job-only-if-folder-changed/118292/13
• Add linting with both jshint and eslint
• Investigate creating a machine image that can be reused for the tests, rebuilt only when config/ changes:

https://docs.github.com/en/actions/creating-actions/creating-a-docker-container-action
https://linuxhit.com/how-to-create-docker-images-with-github-actions/
https://stackoverflow.com/questions/39626579/is-there-a-way-to-combine-docker-images-into-1-container
https://github.blog/changelog/2020-08-07-github-actions-composite-run-steps/
https://dev.to/github/build-github-actions-with-a-docker-container-37e2
https://docs.github.com/en/actions/guides/storing-workflow-data-as-artifacts
https://evilmartians.com/chronicles/build-images-on-github-actions-with-docker-layer-caching

**
https://github.com/lewkoo/reusable-gh-action-workflows
https://github.com/cdalvaro/docker-salt-master/blob/1b862039dc0acd709e972d3619c57b9ef614d6b5/.github/workflows/build-and-test.yml
https://github.community/t/whats-the-recommended-way-to-pass-a-docker-image-to-the-next-job-in-a-workflow/17225/19
**