LEAH-1884: [WIP] DeviceController Improvement
- got a potentially solid idea on how to design the models and controllers
- the idea is completely implemented in brightness.
- valid implementations are usbmount, brightness, wifiscan.
- other than brighness other ones need a final review.
- Note: if the requested value is not valid in toByteArray application would be better to rever like the one is done in fromByteArray. to test set the range of the brightness slider to 0 to 6.
- extra setting models need to be removed like the device controller.
