Changes

Auth

• Refactor SessionStatus by @jan-tennert in #725
  • Move SessionStatus to its own status package
  • Rename SessionStatus#LoadingFromStorage to SessionStatus#Initializing
  • Rename and refactor SessionStatus#NetworkError to SessionStatus#RefreshFailure(cause)
    Note: The cause can be either RefreshFailureCause#NetworkError or RefreshFailureCause#InternalServerError. In both cases the refreshing will be retried and the session not cleared from storage. During that time, the session is obviously not usable.