Definition of what device types can be assign to assets

When defining an asset, you can currently define which child asset types and properties an asset has. However, devices can also be assigned to an asset. Currently, there is no way to specify or limit the selection of devices.

However, when defining the asset structure, it is possible that certain devices may only be assigned to certain asset types. I suggest that we add "Assignabel device type" or something similar to an asset type. If its empty, all device types can be assigned. Otherwise only the defined types will be shown on the dialog creating an asset.