Run "rke2-killall.sh" before shutdown

Create a service to run script `rke2-killall.sh` to stop all the
running containers.

Signed-off-by: John Liu <john.liu@suse.com>

package/harvester-os/files/etc/systemd/system/rke2-shutdown.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=Kill RKE2 Containers for clean unmount
+DefaultDependencies=no
+RefuseManualStart=yes
+Before=reboot.target halt.target shutdown.target poweroff.target umount.target final.target
+
+[Install]
+RequiredBy=reboot.target halt.target shutdown.target poweroff.target umount.target final.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=-/usr/local/bin/rke2-killall.sh

package/harvester-os/files/system/oem/91_rke2-shutdown.yaml

@@ -0,0 +1,7 @@
+name: "Enable RKE2 shutdown service"
+stages:
+  initramfs:
+    - name: "enable rke2-shutdown.service"
+      if: 'grep -q root=LABEL=COS_ACTIVE /proc/cmdline && [ -n "$(blkid -L COS_ACTIVE)" ]'
+      commands:
+        - systemctl enable rke2-shutdown.service