Device should load model on initial creation

At the moment a device create via gosdnc dev create simply exists as dummy in the controller, as no initial communication with the device does take place.

Therefore we have no idea of the current configuration of the device.

The solution is a request against the root / of the devices yang model.

We should discuss if this should be the default or we should a new api call on a pnd e.g. activeDevice, to actually get the devices config.