* Store instance name in Thread router discovery
Store the DNS-SD instance name in the Thread router discovery message.
The instance name is the actual name given to a Thread border router,
e.g. when configuring the name of a Thread border router in Apple Home
the name appears as the DNS-SD instance name. This will allow to make
the Thread border router list more user friendly.
* Use instance_name_from_service_info to get instance name
88ad7e98e0