Setup pre-commit hooks

[crich011]

At a minimum, we should configure pre-commit for this repository to prevent commits to the main branch. (See: example)

This should also include the addition of some notes in the README to explain setting up pre-commit for anyone unfamiliar.

Are there additional hooks that are worth setting up? If we are going to be doing more work in python, black and/or flake8 hooks might make sense. Are there others beyond those?

[crich011]

Moving from private to public visibility allows us to enable branch protection without any pre-commit setup, so setting up pre-commit can be less urgent and require less documentation. Configuring CircleCI to perform any desired checks (e.g. black or flake8) is now also an option, since merging can be blocked on passing checks.