add Prettier for consistent code formatting

[sto3psl]

This PR adds code formatting on commits with Prettier and lint-staged. This should make the dev experience a little better since no one should think about formatting code and instead just get going and develop awesome stuff.

I used lint-staged in favour of pretty-quick or precise-commits with the thought of adding an eslint config later to the pre-commit. Neither pretty-quick nor precise-commits offer this.

🏠 Internal

• adds configuration for Prettier and formats the existing codebase
• set up pre-commit hook to format changed files before commits

New dev dependencies:

• prettier
• lint-staged
• husky

[hshoff]

Yesssssssss, love this! Thank you @sto3psl 🎉