Implement messenger client

Package.swift

...MessengerClient/Messenger/Functors/MessengerConnect.swift

...XMessengerClient/Messenger/Functors/MessengerCreate.swift

...engerClient/Messenger/Functors/MessengerIsConnected.swift

...ssengerClient/Messenger/Functors/MessengerIsCreated.swift

...essengerClient/Messenger/Functors/MessengerIsLoaded.swift

...sengerClient/Messenger/Functors/MessengerIsLoggedIn.swift

...ngerClient/Messenger/Functors/MessengerIsRegistered.swift

.../XXMessengerClient/Messenger/Functors/MessengerLoad.swift

...XXMessengerClient/Messenger/Functors/MessengerLogIn.swift

...essengerClient/Messenger/Functors/MessengerRegister.swift

Sources/XXMessengerClient/Messenger/Messenger.swift

Sources/XXMessengerClient/Messenger/MessengerContext.swift

...es/XXMessengerClient/Messenger/MessengerEnvironment.swift

Sources/XXMessengerClient/Unimplemented.swift

Sources/XXMessengerClient/Utils/MessengerFileManager.swift

...es/XXMessengerClient/Utils/PasswordStorage+Keychain.swift

...lientTests/Messenger/Functors/MessengerConnectTests.swift

...ClientTests/Messenger/Functors/MessengerCreateTests.swift

...tTests/Messenger/Functors/MessengerIsConnectedTests.swift