Sorted out some more threading issues
Removed a redundant SyncPushTokensJob run
Fixed an issue where the NotificationServiceExtension could incorrectly setup the database before setting up it's context
Fixed a few warnings
Removed a bunch of legacy code
Refactored the MainAppContext from Objective C into Swift
Copy tweak
Added a toast when copying the sessionId or group URL (fixes to the toast UI as well)
Fixed the new conversation screen styling
Fixed the styling of the various attachment screens
Updated the buttons on the attachment screen to behave like the input view buttons
Removed the old OWSNavigationBar and OWSNavigationController (logic was buggy and not actually needed in most cases)
