Initial reusable HA kiosk MQTT controls

runtime/ha-kiosk-availability.service

@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+[Unit]
+Description=Home Assistant Kiosk MQTT availability
+After=network-online.target
+Wants=network-online.target
+StartLimitIntervalSec=0
+
+[Service]
+Type=simple
+EnvironmentFile=%h/.config/ha-kiosk/systemd.env
+ExecStart=%h/.local/lib/ha-kiosk-mqtt-control/availability-watch.sh
+ExecStopPost=/usr/bin/mosquitto_pub -r -t ${STATUS_ROOT}/${KIOSK_ID}/availability -m OFF
+Restart=always
+RestartSec=10
+
+[Install]
+WantedBy=default.target