Meta: Dev/test environment speedups

[jherland]

Making use of newer and faster tools to speed up our test runs and improve the developer experience:

• ruff to replace pylint and black.
• uv to replace pip.

Tasks

• Introduce ruff (PR Add the ruff linter #424)
• Configure ruff to replace pylint (PR Make ruff much stricter #425)
• Remove pylint (PR Remove pylint #426)
• Simplify lint pipeline to only run once (instead of once per Python version) (added to PR Remove pylint #426)
• Configure ruff to replace black (PR Use ruff format instead of black #427)
• Remove black (PR Use ruff format instead of black #427)
• Introduce uv (added via nox[uv] in PR Use uv instead of pip to manage virtualenvs #432)
• Use uv instead of pip where applicable (PR Use uv instead of pip to manage virtualenvs #432):
  • in Nox sessions
  • wherever we invoke pip our test suite
  • use uv with fallback to pip in our install_deps logic.