Setup GitHub Actions to handle testing PRs and conducting snapshot deployments

[dbwiddis]

Checking whether PRs break tests is currently done manually. GitHub Actions are easy to set up, very capable, and helpful to automate testing and other things. You could easily:

• Run unit tests on every push to a PR or merge to the main branch (and test across multiple JDK versions)
• Deploy SNAPSHOT versions on every merge to the main branch
• Send your code to static analysis tools like Coverity and Sonarcloud

Happy to submit a PR to get you started on this if you'd like.

[cegredev]

I've been wanting to do this, but didn't get around to it yet, so yes, I would absolutely love some of your help! :D