Improvements to our commit-hook (lint-staged)

- [ ] Switch to using `prettier-eslint` for linting and formatting files along with calling `git add` when done.
- [ ] Run Prettier on CSS/Less files as well.
- [ ] Make sure the messaging about what's going on is clear, as it might be confusing to new developers. 
- [ ] Run flake8 when the developer using our Docker setup