Add support for Logitech Unifying Receivers
Logitech's unifying receivers have pretty much the same workflow as Bluetooth, with a few differences.
When one or more unifying receivers are present, we'd need a way to:
- list the receivers
- list the devices associated with each receiver and their current status
- forget "paired" devices
- pair new devices (this happens by starting the pairing process, and turning on the new device, or turning it off an on)
Benjamin Tissoires, Hans de Goede, Peter Hutterer and myself probably know enough about those receivers and devices to answer technical questions if necessary.