feat: component & props listing

[AndersDJohnson]

Show a listing of all components and their props that you can point & click - this will enhance discoverability. I realize you can hit < to see components or space after <MyComp to see props, but it's not as obvious. Existing autocomplete support is great but only goes so far if you don't know what to start typing (especially without fuzzy support #126).

[askoufis]

Thanks for the issue.

Playroom's editor is designed to show you appropriate suggestions as you write JSX. It's a bit unclear how/where we would show this list of components and/or props. I'm going to close this issue for now, but please feel free to re-open it with more specific details if this is still relevant to you.