chore: Add Storybook MVP

[dgca]

What changed? Why?

Adds Storybook and a couple of demo stories to test out Chromatic and upcoming docs migration support

Notes to reviewers

Styling doesn't work at the moment. Two options for how to fix:

1. We can change the base branch of chore: Prefix component classnames #2310 to main. That will switch our Tailwind setup to use Vite. This will be a breaking change, but will actually unblock a couple teams who have asked for this.
2. We can set up Postcss to compile Tailwind styles. This will be more work, but wouldn't require breaking changes.

How has it been tested?

Manually

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Name	Status	Preview	Comments	Updated (UTC)
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[cb-heimdall]

🟡 Heimdall Review Status

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Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1