Update to StoryBook 8

[JeremyRH]

Fixes: #33 #35

• Drop support for StoryBook version 6 & 7.

• Drop support for React 16. Use react/jsx-runtime for jsx.

• createLiveEditStory changed to accept all story fields.

  // Before:
  export const StoryA = createLiveEditStory({ code: StoryASource });
  // Had to mutate the Story
  StoryA.args = { foo: 'foo' };

  // After:
  export const StoryA = createLiveEditStory({
  code: StoryASource,
  args: { foo: 'foo' },
  });

• Remove automatic configuration for webpack.

• MDX updated, some breaking changes.

• Update TypeScript which may cause breaking changes in types.

• Add package.json "exports" and "type: module".