ruff stylechecking

[gsarti]

Description

This PR replaces isort, flake8, bandit, pylint and pyupgrade with the ruff library, both for regular quality checks and for pre-commit validation.

The main benefits for such replacement are:

• A centralized, dependency-free tool for most style checks.
• Blazing fast, avoid waiting on every pre-commit (was ~4min because of flake8, down to a fraction of a second now).
• Close compatibility to previous stylechecking, with the exception of some isort formatting that is ok to drop.

The currently committed settings are already good, but tests are failing because the codebase wasn't update according to the new stylechecker. Waiting for #148 and #157 to get merged in main to apply all style updates in a single pass and merge.