More prosody optimisations to reduce battery and bandwidth use on mobile

src/freedombone-app-xmpp

     echo '  "http";' >> $filename
     echo '  "http_upload";' >> $filename
     echo '  "websocket";' >> $filename
+    echo '  "throttle_presence"; -- Reduce battery and bandwidth usage' >> $filename
+    echo '  "filter_chatstates"; -- Reduce battery and bandwidth usage' >> $filename
     echo '};' >> $filename
 }