Add Gutenberg react and framing discussion points.

[magnificode]

Description of the Change

This PR brings in Gutenberg documentation from the FEE exploration of Gutenberg. Specifically touching on React's role in Gutenberg, as well as how Gutenberg should be framed as a supplementary tool for publishers.

Checklist:

• [x] I have read the CONTRIBUTING document.
• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my change.
• [x] All new and existing tests passed.

[timwright12]

@tlovett1 @brentvr This is the first of the Gutenberg PRs if you don't mind putting some eyes on it