* Put KeyBackupService in its own folder
* Put SDSKeyValueStore in its own directory
* Put SDSDatabaseStorage in its own directory
* Stop doing useless dispatches in SDSTransactable
* Add V2 DB classes
* Wrap SDSKeyValueStore in a protocol and factory
* Make TSConstantsProtocol public to take it as a param in other places
* Take explicit transactions and do single lookups in TSAccountManager registration state methods
* Take explicit transaction on OWS2FAManager
* Make KeyBackupService an instance that takes dependencies on init
* Protocolize KeyBackupService
* Put Dependencies+SSK in its own directory
* Add DependenciesBridge
* add ViewControllerContext
* used shared context in OnboardingController
* Don't check KeyBackupService in RemoteConfigManager; the one and only callsite already checks it separately
* All the random cleanup that needed to happen to get the app to build again.
* Add mock dbv2 classes
* Migrate existing KeyBackupServiceTests
* Namespace KBS shims
* DBV2 -> DB, after changing the min swiftlint type length to 2 chars
* add toy example
* Unwrap writes as reads
* pr comments
* pr comments 2: return of the nits
* final Pr comment
