shell: Network Manager transfers Addresses in network byte order

See the documentation here:

https://developer.gnome.org/NetworkManager/unstable/spec.html

This is pretty standard way to represent addresses as evidenced
by the htonl() and ntohl() libc functions. Network byte order
is MSB.

We don't need to track the host's byte order. Any DBus interface
that makes us do this is broken, and needs some sorta work around,
perhaps a flag in the dbus interface, or in com.redhat.Cockpit.Manager.
But that's not the case here.