fix: tune reboot timeout on panic, improve shutdown ulcmd support

* Ensure we have all the right targets for ulcmd-shutdown-hook to show the shutdown message
* Move to an init script that we can use for setup commands, like adjusting our kernel panic timeout.

overlay/filesystem/etc/systemd/system/ubnt-init.service

@@ -1,10 +1,10 @@
 [Unit]
-Description=Load UBNT kernel modules
+Description=UBNT bootup init script
 
 [Service]
 User=root
 Type=oneshot
-ExecStart=/usr/sbin/modprobe ubnthal
+ExecStart=/usr/lib/init/boot/ubnt-init.sh
 RemainAfterExit=yes
 
 [Install]

overlay/filesystem/etc/systemd/system/ulcmd-shutdown-hook.service

@@ -1,11 +1,11 @@
 [Unit]
 Description=ulcmd shutdown hook
 DefaultDependencies=no
-Before=shutdown.target halt.target
+Before=shutdown.target halt.target poweroff.target
 
 [Service]
 ExecStart=/usr/bin/ulcmd --sender system-hook --command poweroff
 Type=oneshot
 
 [Install]
-WantedBy=shutdown.target halt.target
+WantedBy=shutdown.target halt.target poweroff.target

overlay/filesystem/usr/lib/init/boot/ubnt-init.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+# Load our kernel modules
+/usr/sbin/modprobe ubnthal
+
+# Set our kernel panic timeout SUPER short so we reboot on crash
+echo 2 > /proc/sys/kernel/panic

scripts/docker/bootstrap/001-bootstrap

@@ -16,7 +16,7 @@ apt-get update
 apt-mark hold linux-image-* # We do not want these, as we run our own kernel!
 
 # Setup our services
-systemctl enable load-ubnt-modules
+systemctl enable ubnt-init
 systemctl enable mock-ubnt-api
 systemctl enable ulcmd
 systemctl enable ulcmd-reboot-hook