Update generate component script to use TypeScript

[matthewgallo]

What will this achieve?

When we create new components, there is a generate component script that can be run to scaffold the correct setup of files, configuring package-settings, exporting the new component. This is an issue to think about when the right time is to have the actual component itself moved from .js to .tsx file.

I don't think we need to set a timeline on this for now, but wanted to make sure it's something we plan for later on.

[elycheea]

Agree. Putting this in the icebox for now since in some previous discussions, we said not to require TypeScript for new components. We might be reaching the point soon where we should start shifting to TypeScript on default though. 🤔

[AlexanderMelox]

Are we still keeping PropTypes in the generate or just Typescript props?

DISPLAY_NAME.propTypes = {
  /**
   * Provide the contents of the DISPLAY_NAME.
   */
  children: PropTypes.node.isRequired,

  /**
   * Provide an optional class to be applied to the containing node.
   */
  className: PropTypes.string,

  /* TODO: add types and DocGen for all props. */
};

[matthewgallo]

For now we'll keep both until something more concrete has been decided from #4466