feat: implement lint and unit test ci, extend mise tools manifest

[oddgrd]

• Implement basic CI with unit test running and cppcheck linting.
• Correctly git add the rtt submodule.
• Commit the stm32cubemx generated drivers files, that were previously gitignored. They are needed for tests, and for reproducible builds of the project, without needing to run stm32cubemx to generate them.