Write plinth api to json file

src/freedombone-utils-android

     fi
 
     local_hostname=$(grep 'host-name' /etc/avahi/avahi-daemon.conf | awk -F '=' '{print $2}').local
-    plinth_api="/var/www/${local_hostname}/htdocs/plinth/api/1"
+    plinth_api="/var/www/${local_hostname}/htdocs/plinth/api.json"
 
     # Create a self-signed cert if needed
     # The FreedomBox app assumes a self-signed cert