Better organize components and screens

[brettdh]

Motivation

The components directory has grown massive, and it's not clear how different components relate to each other. Further, though it was originally intended to only contain common components that are used in a variety of places throughout the app, it is basically now a dumping ground for almost every component in the app - including many that are only used by one screen.

This clutter makes it hard to understand the structure of the app and, thus, presents a significant barrier to new contributors. We should tidy this up.

Plan of action

• Identify components only used by one screen and move them closer to that screen
• For remaining components, try to find a more logical organizational structure
• Update the somewhat neglected Storybook for the common components
• (bonus) Host the storybook in Netlify or now.sh or something, with a link from the readme
  • Goal: make it trivially easy for anyone to see what components are available and what they're called, without doing any dev setup