Commands abstraction

• Created abc classes which commands could inherit from:
  • Command (a command with no result)
  • CommandWithResult
  • CommandPasswordSecured (a -yet- simple command that requires the password, to separate the commands that require it)
  • CommandRestricted (command that is restricted by some condition (look at CommandInActive)
  • CommandInActive (command that requires the app to be in active mode)
• New command - RemoveKey
• Show calculated public key when creating a new authority
• Created ConfirmWithPassowrd screen
• Created FailedCommandNotificator context manager that suppresses errors resulting from commands and just notifies about it
• WriteToBeekeeper is now SyncDataWithBeekeeper and also handles new keys that appeared in beekeeper and not clive
• Introduced try_again_after_activation decorator