Automated testing

[Didgy74]

• [x] Create Docker image
• [x] Set up Github Actions
• [ ] Set up Github Actions runner
  • [ ] Use NTNU OpenStack?
• [x] Make sure automated tests can catch build errors
• [x] Make sure automated tests can stop a merge if tests fail
• [ ] Write build instructions for Linux and Windows, including how to run tests and build Docker image
• [ ] Write about that we used WSL
• [ ] Graphics testing with Lancelot?