Move to create-react-app

[thomaseizinger]

Problem

The current webpack setup is super painful and doesn't allow us to use things like storybook.

Goal

Ideally, we can use create-react-app without any extra configuration.

The main blocker I see in this regard is our component styling using SASS and react-toolbox.
#295 is working on replacing this with tailwind, which should drastically simplify this setup.