Add CI checks

[DNedic]

In order to avoid introducing regressions, either functional, style or policy we should consider adding a CI pipeline.

Some things we could add to the CI:

1. Make sure our firmware builds
2. Make sure we don't introduce any sources with incompatible licenses or forget to add license notices
3. Enforce formatting rules
4. Possibly run static analysis and/or other tools to find issues

[mileticveljko]

Do you think GitHub Actions meets our requirements?

Perhaps this Issue can include adding Cmake target for code formatting and possibly for adding license notice to source files without one - so that process is automated for developers.

[DNedic]

Usually this process is automated outside of the build system, using tools like pre-commit (see example here) and I do think we should add this as well.

[DNedic]

Code formatting and pre-commit hook is added here, if/when merged, we should add a GitHub workflow to run pre-commit hooks in the CI.

[mileticveljko]

GitHub action that runs pre-commit in CI added. PR: #22