Removed the dependency of the DiscoveredCloudPrintersModel on CloudOutputDevice,
which is Ultimaker specific. This can allow even external plugins to add to this
model in the future.
CURA-7022
Have a separate model to hold the discovered ultimaker cloud printers.
This model will be used to communicate across the application that new
cloud printers have been found which they weren't seen before.
CURA-7022