Add Editor and Layout in @wordpress/edit-post (Ported from Gutenberg Mobile)

[Tug]

Description

This is step 8b of wordpress-mobile/gutenberg-mobile#958
This PR ports the gutenberg-mobile AppContainer and MainScreen to gutenberg as the Editor and Layout components inside @wordpress/edit-post.
This is not needed to implement Inner blocks for mobile native but is a nice improvement which will help port the remaining of our code to gutenberg.

How has this been tested?

GB Mobile PR wordpress-mobile/gutenberg-mobile#1171

Types of changes

Adds native support for Editor and Layout

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[etoledom]

Great job! 🎉

Tested via wordpress-mobile/gutenberg-mobile#1171 (review)

JS unit test are failing on CI, but they are passing locally.
Maybe retrying will help!

[Tug]

@etoledom Thanks fo the review 🎉

JS unit test are failing on CI, but they are passing locally.

I rebased but they're failing on master as well

[hypest]

I think that the changes related to what happens on html/visual mode switch introduced a regression (Case A in wordpress-mobile/WordPress-Android#10092 (comment)).

Any context about why the mode change tries to send data to the the parent app? @Tug , can you elaborate about these lines? :

// refresh html content first
this.serializeToNativeAction();