cloud-setup: add pre-up event to prevent reaching network-online.target
network-online.target should not be reached before nm-cloud-setup completes configuring the network, which may make user service get started before the network is fully configured.
Setting nm-cloud-setup.service as "Before=network-online.target" would maybe have already achieved that. However, also use a pre-up dispatcher script, so that the device activation in NetworkManager is also waiting for nm-cloud-setup to complete.