always use connman to connect to cellular services

connman provides better error messages.
update the network configuration list when changes in the networks
happen.
make Discovered dependent on autoConnect.

and make QNAM uses sessions, so we get the desired effect of
our connection dialog popping up when someone tries to make
a connection/get, etc when there is no connection.

This forces the connection dialog to popup for all
but autoconnectable services.

It also has the effect that QNAM will wait for a
connection in some instances.