WIP: Registration

Registration is here!

Added

• Registration (closes #71)
• Login with SSO
• Login with Access Token (for #98 (closed))
• Deep linking with a configurable scheme
• Created reusable functional and styled components

Changed

• The configuration has switched from the .env file to app.json
• Modified the Login UX to match the registration (might solve #81)
• Replaced the blobs by themable SVGs

Removed

• react-native-dotenv

Fixed

• Paste is available on inputs on Android (fix #80)

To test it

• mozilla.org allows you to test SSO login. In the app.json you can put the temporary https://auth.dropinthepond.ml/ auth gateway (it will even work without it, if you want to try too).
• matrix.org should allow you to test most of the Sign Up screens, and the default Login, of course.
• Maybe try with some servers without well-known to make sure it works: disroot.org, chat.librem.one...

TODO before merge

• Only the login/sign up inputs have the paste fix so we have to change the others too
• Set up deep linking for the dittochat scheme on iOS
• Pod install
• Test on iOS
• Choose default homeservers
• Write translatable homeserver descriptions
• Make sure the Auth gateway works, then set it up on ditto.chat