Implement Sizzle UI Library

**GOAL**: Create a foundation for having a UI library.

This includes implementing common atomic tokens:
- colors
- typography
- spacing
- radiuses

atomic widgets:
- text
- textinput
- buttons
- card
- dropdown

Additionally, this includes creating a UI Library Showcase app. This should not be a Widgetbook/Storybook app. Instead, it should be a fully custom implementation.