Add GitHub Actions to test PRs and create releases

[Prof-Bloodstone]

Perhaps stealing https://github.com/Prof-Bloodstone/WanderfulAdditions/tree/master/.github/workflows is good enough?

DoD:

• When a PR is created, plugin is built and tests ran
• When a release tag is create, plugin is built, release created and plugin uploaded to the release

[Prof-Bloodstone]

It is being built, but still needs the release to be automated.