Rather than duplicating the implementation of `network`, this allows ESP32
to use the shared one in extmod. In particular this gains access to
network.hostname and network.country.
Set default hostnames for various ESP32 boards.
Other than adding these two methods and the change to the default hostname,
there is no other user-visible change.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
