Initialize design system

[josh-chamberlain]

https://www.designsystemchecklist.com/

• [x] CSS setup
  • [x] global CSS to start, component-level things can come later
  • [x] utility classes, organized
  • [x] responsive styles, organized
  • [x] merge duplicate selectors
• [x] HTML components
  • [x] buttons
  • [x] navigation
  • [x] code line and block font style
  • [x] anything from /pdap.io
• [x] documentation of purpose and principles
• [ ] getting started guide for integration
• [x] consider using storybook