Add a documentation page about the block editor settings

[youknowriad]

Related #53874

What?

Just documents some of the most important settings a user can pass as a prop to the BlockEditorProvider component. I think we're still missing the "theme.json" settings and styles from this list but these should be added when we decided on a stable name.

Test the documentation website

cd platform-docs
npm install
npm start

[ntsekouras]

LGTM, thanks!

[aaronrobertshaw]

These docs are looking great, nice work 👍

I spotted a couple of typos so have left inline comments for those and some other minor tweaks

[ramonjd]

LGTM!

Left some predictably pedantic suggestions.

"Whether or not" is interesting though - it's mostly used when the outcome is not important. Like, "Whether or not Github allows threads in comments, I'm still going to use it!"