Provide type extension to make apolloClient parameter type-safe

[oosawy]

As done in manager.ts, the ambient module declaration can be used be extend Storybook's Parameters type to include apolloClient and its type. But the declaration doesn't appear in the compiled code.

storybook-addon-apollo-client/src/manager.ts

Lines 7 to 9 in 029aea6

	declare module "@storybook/react" {
	interface Parameters extends ApolloParameters {}
	}

It would be nice if it works type-safe out of the box, but TypeScript only loads types if it imported or the package is @types/* AFAIK.

So I'm thinking about add a new entry point like storybook-types providing the declarations, and letting the user import it to get full type-safety.

Another option: Tell users to add the following code to something.d.ts in README

import { MockedProviderProps } from "@apollo/client/testing";

declare module '@storybook/types' {
  interface Parameters {
    apolloClient?: Partial<Omit<MockedProviderProps, "children">>;
  }
}