feat(mocks): improve addon setup for storybook-builder

[bashmish]

What I did

For Storybook 7+ (@web/storybook-builder):

1. make a single entry point @web/mocks/storybook-addon with automatic setup
2. explain how to setup interceptor without using the argument interceptor in mockRollupPlugin({ interceptor })
3. clarify in docs in which files changes are not necessary because people now just copy the code, even if it says it's for Storybook 6

This is pretty hard to support 2 docs for very different setup side-by-side, I hope to deprecate the Storybook 6 one soon and release @web/mocks v2 without it.

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 59d538617ca5fb0fdfe3df16fd696a164a615a01

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ---------- | ----- | | @web/mocks | Minor |

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