Theming Storybook with an Emulsify theme

[amazingrando]

Theming Storybook with an Emulsify theme

This PR styles the Storybook interface to "brand" it as Emulsify. It is still obviously Storybook, but now it looks like Emulsify's implementation of Storybook.

Ticket

https://app.clickup.com/t/36718269/EMULSIFY-56

How to review this pull request

• [ ] Run npm run develop
• [ ] Confirm the interface looks like the image below.
• [ ] Explore the interface—open controls, click on buttons, etc—and confirm there is not something that looks weird or off. (I think I caught all of the edge cases, but I appreciate your eyes on this.)

[mariannuar]

This ticket is ready for review again. Whoever reviews it, please take it in count that font-sizes values are not being displayed as expected. For example, the cover looks terrible but it's because of that. There's another PR that fixes this. https://github.com/emulsify-ds/emulsify-ui-kit/pull/114