Comment 1 for bug 1737630

The goal is that cloud-init should not have to call netplan apply.
Rather, cloud-init runs Before=network-pre.target. Then, the normal
processes that would bring up networking will run After network-pre.target,
and they'll see and consume the files that cloud-init (and netplan generate)
wrote.

The goal is basically that this is the same as if cloud-init wrote
those files and then did a /sbin/reboot.