Usermod config level up, step 2: Working!

- remove settings_um2
- remove addToConfigMenu
- settings.htm: add isO and ldS (inspired by settings_um.htm): add usermod buttons to urows
settings_um.htm: check url um var and if set show only this usermod. Only show globalGPIOs if no usermod

usermods/audioreactive/audio_reactive.h

@@ -1418,10 +1418,6 @@ class AudioReactive : public Usermod {
       sync[F("mode")] = audioSyncEnabled;
     }
 
-    void addToConfigMenu(JsonObject& root) {
-      JsonObject top = root.createNestedObject(FPSTR(_name));
-    }
-
 
     /*
      * readFromConfig() can be used to read back the custom settings you added with addToConfig().