build: Use GitHub Actions to run tests

[Johni0702]

No description provided.

[github-actions]

Test Results

95 tests   95 ✔️  15m 7s ⏱️
15 suites    0 💤
15 files      0 ❌

Results for commit 9eecce4.

[DJtheRedstoner]

Is there a specific advantage to splitting up each test class as a separate job?

[Johni0702]

Is there a specific advantage to splitting up each test class as a separate job?

Parallelism. This way all the tests can run in less than three minutes, compared to 15 if ran in sequence (or probably around 9 with the two cores the standard github runner has).
Would of course be less of a resource waste if they just allowed you to provision more cpu cores for certain steps, but they don't (without paying for a larger runner, and why would you when you can just provision many small ones).