ci: add ruff formatter and linter

[tachyonicClock]

Linting is the process of automatically checking code for style, syntax, and other issues. Code formatting ensures code meets a consistent style. Together they help ensure the codebase is consistent and clean. Developers don't have to worry about formatting and reviewers can focus on code rather than style preferences.

CapyMOA uses the ruff linter to enforce both. Checks are run automatically using GitHub actions on every pull request.

You will need to run ruff locally before committing changes. Ruff is installed as part of the development dependencies.

To format files run:

ruff format # or python -m invoke format

To lint files run:

ruff check # or python -m invoke lint

Furthermore, python -m invoke commit will run the linter and check that formatting is correct before committing.

These explanations and instructions have been added to docs/contributing/vcs.md