[connman] separate services and technologies processing

Technologies provide information about tethering: "Internet.Tethering"
property is newline-separated list of interfaces with enabled
tethering. Services providing other properties: first service in the
list is used for it (interface for default route), and services and
technologies are reprocessed when default service is disconnected.

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>