Add connectivity status
Status is currently hardcoded to CONNECTED, though it's possible for AirPort base stations to be reachable and have no upstream connectivity (i.e. Internet connectivity). This should be retrieved from the sySt property (and ignored if set in syIg).
Also maybe add custom characteristics for IP addresses (waIP if device is a router, laIP, dhSL, 6Wad if router, 6Lad).