saveData method
Implementation
void saveData(String host, String username, String passwordOrKey, int port,
    int screenAmount) {
  _sshData.host = host;
  _sshData.passwordOrKey = passwordOrKey;
  _sshData.username = username;
  _sshData.port = port;
  _sshData.screenAmount = screenAmount;
  notifyListeners();
}