Add pre-commit config for black and isort

[carlthome]

Just a suggestion but it would be nice to have auto-formatting with black running on this repo, to not have to think manually about code style.

[akx]

It would probably be even better to use ruff and ruff-format instead of black and isort :)

[carlthome]

I like ruff but my hesitation is that it's from a VC backed tech startup (https://github.com/astral-sh) rather than a FOSS community (https://github.com/psf), so it will probably start pushing premium features and ads eventually (like things usually go when VC is involved).

With that said, ruff is fast and convenient, so maybe why not? 😅