[Monorepo] import gutenberg-mobile as a package

[dratwas]

Description

Explores #11491.
Superseeds #17456 started by @Tug

Wordpress-iOS PR - wordpress-mobile/WordPress-iOS#12762
Wordpress-Android PR - wordpress-mobile/WordPress-Android#10668

This is a migration of gutenberg-mobile to gutenberg repository.

New packages added:

• @wordpress/react-native-editor - playground react-native app and bundle entrypoint
• @wordpress/react-native-bridge - module which starts react-native inside the client app (WP-iOS/Android)
• @wordpress/react-native-aztec - react-native-aztec module

Usual yarn commands ran from gutenberg-mobile are now accessible from gutenberg using npm run native

For instance:

yarn start => npm run native start

How has this been tested?

TBD

Screenshots

Types of changes

Add new native packages, for native build, unifying the 2 repositories

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.
• I've imported git history
• I've checked that the licencing is OK
• I've checked that package release is working as expected (lerna)
• I've checked that installing dependencies works as expected and that changes to package-lock.json are OK
• I've checked that we are up to date with gutenberg-mobile develop branch
• I've informed concerned developers of the change of repository
• I've ported e2e tests iOS
• I've ported e2e tests Android
• I've ported pre-commit hooks including eslint
• I've ported i18n
• I've checked that build scripts are up to date with WordPress-iOS
• I've checked that build scripts are up to date with WordPress-Android
• I've checked that WordPress-iOS works properly after migration
• I've checked that WordPress-Android works properly after migration
• I've made sure that the project can be opened in Android Studio
• I've made sure that the project can be opened in XCode
• I've made sure that the demo app for mobile runs
• I've made sure that I have excluded any binary files, jar, phar... from the patch (gutenberg-mobile has gradle-wrapper.jar committed to the repo though and we might want to fix that later?)
• I've checked that all CI steps are imported
• i've checked that the react-native-aztec example app works