Setup common text styles and heading sizes

[edmundito]

Create a common way to specify the type of text based on the size and styles. Add that to the webapp with a storybook example but don't update any existing components.

Requirements

• Styles: Ensure there is a way to specify font weights for what's bold/strong, italic/emphasis and possibly colors.
• Sizes: Ideally, heading sizes and heading types are decoupled (for a11y reasons.). Sizes should be based on t-shirt size (sm, md, lg, xl)
• API: Proposed approaches in doc

Use this webflow page for updated design:
https://airbyte.com/design/designtext

Figma needs to be updated to match what's on webflow:
https://www.figma.com/file/gMNRYVJav25pdsoxAyW7Qp/00_01_WEB-APP-LIBRARIES?node-id=2%3A391

[octavia-squidington-iii]

cc @airbytehq/frontend