systemd-conf: configure wired network with dhcp

systemd-conf: configure wired network with dhcp

Add a configure file for systemd.networkd to configure wired network
interfaces with dhcp. It works with common network interfaces such eth0
and eno1. And do not install it for qemu bsps.

Refer to
https://github.com/YoeDistro/meta-yoe/tree/master/recipes-core/systemd

[YOCTO #13057]

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>