Ruff is a very fast linter implemented in Rust and it can act as a drop-in
replacement for flake8. When running the same set of rules across all files
in mozilla-central (without mozlint), flake8 takes 900 seconds whereas ruff
takes 0.9 seconds.

Ruff also implements rules from other popular Python linters such as pylint,
isort and pyupgrade. There are even plans to implement feature parity with
black in the future. Ultimately, it can become our one stop shop for all Python
linting and formatting.

This stack will swap out all our Python lint tools for ruff (excluding black
for now).

Differential Revision: https://phabricator.services.mozilla.com/D172313