Adding a numerical prefix ('20-') to the ethernet.network and
wireless.network configuration files for systemd-networkd.
This way overriding them can become more predictable e.g. by providing
files with a '30-' prefix.
Closes#13
configs/releng/airootfs/etc/udev/rules.d/81-dhcpcd.rules:
Removing the udev rule for starting dhcpcd@.service on interfaces of the
form eth* and en*.
configs/releng/airootfs/etc/systemd/network/{ethernet,wireless}.network:
Adding default DHCP configurations for en*, eth*, wlp* and wlan*
interfaces.
configs/releng/airootfs/etc/resolv.conf:
Adding a symlink from /run/systemd/resolve/stub-resolv.conf to
/etc/resolv.conf (in airootfs).
configs/releng/airootfs/root/customize_airootfs.sh:
Adding systemd-networkd and systemd-resolved to the list of services
that are being enabled during airootfs customization.
This makes systemd generate a machine-id on early boot and prevents it from thinking we need
any "first boot" setup. We really don't want systemd thinking that, since we carefully prepared
our root file system.
This also ensures every live environment has a unique machine id.
