remove docs as they get moved to primer/design

[lukasoppermann]

Blocked by: https://github.com/primer/design/pull/387

Only merge once 387 is merged

This PR removes the docs here in favor of the new icon docs in primer/design.

Changes:

• deleted docs folder
• deleted npm scripts that build docs
• deleted workflows that build docs

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 0356c685bff9c8409e7137abcd0fe46c821511a1

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[ollie-iterators]

https://github.com/primer/design/pull/387 has been merged

[ollie-iterators]

Any reason why this isn't getting merged?