python3-ble2mqtt: add init script

Note that init script won't do much without configuration provided.
The init script comes from the upstream README file.

Also add missing dependency.

Signed-off-by: Quintin Hill <stuff@quintin.me.uk>

lang/python/python-ble2mqtt/files/ble2mqtt.init

@@ -0,0 +1,15 @@
+#!/bin/sh /etc/rc.common
+
+START=98
+USE_PROCD=1
+
+start_service()
+{
+    procd_open_instance
+
+    procd_set_param env BLE2MQTT_CONFIG=/etc/ble2mqtt.json
+    procd_set_param command /usr/bin/ble2mqtt
+    procd_set_param stdout 1
+    procd_set_param stderr 1
+    procd_close_instance
+}