[storybook__react] Add parameter types for add-ons

[do7be]

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[do7be]

Oh, sorry. This pull request is based on alpha version. So this diffs are incorrect.

[typescript-bot]

@do7be Thank you for submitting this PR!

🔔 @joscha @wapgear - please review this PR in the next few days. Be sure to explicitly select Approve or Request Changes in the GitHub UI so I know what's going on.

If no reviewer appears after a week, a DefinitelyTyped maintainer will review the PR instead.

[astorije]

@do7be, now that Storybook v4 is out, would you mind re-submitting this?
Maybe switch parameters from any to object?