ignition: start kubeadm after network.target and containerd.service

In certain baremetal environment, where there are multiple connected
and/or disconnected network ports, the network target is reached more
slowly, and the kubeadm.service might fail because it does not have the
proper pre-kubeadm commands correctly done (like a ctr image pull) or it
cannot connect to other k8s nodes.

bootstrap/kubeadm/internal/ignition/clc/clc.go

@@ -96,6 +96,8 @@ systemd:
         Description=kubeadm
         # Run only once. After successful run, this file is moved to /tmp/.
         ConditionPathExists=/etc/kubeadm.yml
+        After=network.target
+        After=containerd.service
         [Service]
         # To not restart the unit when it exits, as it is expected.
         Type=oneshot