Start of the CI pipeline

[Spartee]

Start of the CI/CD workflow for the python library and actor.

Covered:

• multiple python versions with Tox (3.10+) and pytest
• Docs eventually with mkdocs (commented out for now)
• Linting and formatting with Ruff and prettier
• Codecov

TODO (in this PR):

• include the mypy checks when the mypy errors are resolved.

[nbarbettini]

FYI - in my next branch (https://github.com/ArcadeAI/arcade-ai/tree/Support-Pydantic-models-for-inputs-and-output_Nate-Barbettini) I've fixed the prettier formatting errors that were partially failing this quality check. Some mypy errors still remain (not spending time on those yet).