This provides a standard interface to setting the global networking config
for all interfaces and interface types.
For ports that already use either a static hostname (mimxrt, rp2) they will
now use the configured value. The default is configured by the port
(or optionally the board).
For interfaces that previously supported .config(hostname), this is still
supported but now implemented using the global network.hostname.
Similarly, pyb.country and rp2.country are now deprecated, but the methods
still exist (and forward to network.hostname).
Because ESP32/ESP8266 do not use extmod/modnetwork.c they are not affected
by this commit.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>