Add device-type parameter to service discovery

[MarcusWichelmann]

For easier recognition of a device in the network we could choose different icons for every device. The device type can be set while registering an Avahi service to make it available to every client.

Possible device types can be:

• notebook
• notebook-dual-monitor
• desktop
• desktop-dual-monitor
• phone

Further differentiations between operating systems should be possible using the protocol-implementation key.

[Philip-Scott]

is the differentiation of dual/single monitor really needed for this service
? I think a better approach could be a differ between OS's (windows/mac/linux/android/iphone)

[SoerenBusse]

Yop! Its not interesting if the computer has dual/single monitor. I want to know the OS ;)

[MarcusWichelmann]

It'd help differentiating between desktop pcs. But you're right, recognizing the operating system is probably more important. Like said above, that can be done using the protocol-implemantation key. Or should we add an own key for that?