Add mosquitto configuration for Netz39

this containes the read-bridge from platon

templates/mosquitto.conf.j2

@@ -0,0 +1,15 @@
+user root
+
+persistence true
+persistence_location /mosquitto/data/
+log_dest file /mosquitto/log/mosquitto.log
+
+# Bridge to platon
+connection br-pottwal-to-platon
+address platon:1883
+cleansession false
+clientid br-pottwal-platon
+start_type automatic
+notifications false
+try_private true
+topic # in 2