[WIP] networks: Move initial connection setup to Plinth

Created by: SunilMohanAdapa

Signed-off-by: Sunil Mohan Adapa sunil@medhas.org

This is the last piece required after #1002, that will let us eliminate freedombox-setup's first-run and the reboot after it. Since the networks module's version is not incremented, users upgrading from earlier version of Plinth will never run the setup code. However, images built with the change will end up running the setup code.

Work remaining here is to test.