Linting and coding style guide

To maintain the code quality, it should be considered to include both a linting tool as well as code guidelines.

As linting, we should move forward with ruff. The rules still need to be defined to adapt to our code (for example, using a different line length than 80 characters per line).

For a coding style guide, the Google Python Style Guide is quite complete. Still, a document can be created defining in which rules the code deviates from. The first one being the linter (to not use pylint).