feat: Add Dockerfile and GitHub Actions based CI

[matthewfeickert]

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Before submitting

Please complete the following checklist when submitting a PR:

• [x] All new features must include a test sequence. If you've fixed a bug or added code that should be tested, add a test sequence below for it to be checked by other developers.
• [x] All new functions and code must be clearly commented and documented. If you do make documentation changes, make sure that the docs build and render correctly by running ./doc/makedoc.
• [ ] Add a new entry to the madanalysis/UpdateNotes.txt file, summarizing the change, and including a link back to the PR.

The format of

https://github.com/MadAnalysis/madanalysis5/blob/3fd09e7fc35a27294a19fb6d8b0f45f4620a9caa/madanalysis/UpdateNotes.txt#L1-L11

is confusing (what are the numbers in the first column)? The file also hasn't been updated since MadAnalysis5 got ported to GitHub, so I'm not sure if there is a format the dev team would like to keep.

When all the above are checked, delete everything above the dashed line and fill in the pull request template.

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Context:

Resolves #2

Description of the Change:

• Add a Debian based Dockerfile that builds from the top level of the repository with the build context

docker build --file docker/Dockerfile --tag madanalysis5/madanalysis5:debug-local .

• Add differential cross-section plot example (taken from http://madanalysis.irmp.ucl.ac.be/wiki/FAQNormalMode) as a test example to run after the build.

• Add GitHub Actions workflow to build, test, and publish Docker images.

Benefits:

Dockerfiles and images are very powerful (build) testing and debugging tools and can be exceptional for giving users a sandbox area to play in and to use for demonstrations.

Possible Drawbacks:

PRs are like puppies. While I can help give guidance on how everything works, if this isn't something that the dev team is up for maintaining I can 100% appreciate and respect that.

Related GitHub Issues:

Issue #2.