Make availability_timeout non experimental. #775

lib/controller.js

@@ -59,7 +59,7 @@ class Controller {
             ));
         }
 
-        if (settings.get().experimental.availability_timeout) {
+        if (settings.get().advanced.availability_timeout) {
             this.extensions.push(new ExtensionDeviceAvailability(
                 this.zigbee, this.mqtt, this.state, this.publishDeviceState
             ));