Enables networkd instead of dhcpcd for DHCP/RA. It offers a solid base
for network configuration, that is much more extensible than dhcpcd and
also better maintained than our bespoke `networking.interfaces` modules.
Closes: #287269
Use modulesPath so we don't have to magically rewrite paths in activation script,
set stateVersion to the one this was built with (which should approximate "first install")
