Wire up Account .Storage properties #34
Description
Wire up org.freedesktop.Telepathy.Account.Interface.Storage properties, such as
StorageRestrictions, StorageIdentifier, StorageSpecificInformation and StorageProvider.
StorageRestrictions is wanted for TelepathyIM/telepathy-ofono#1 (account presence service needs to know StorageRestrictions, especially Cannot_Set_Presence.