IPC: added darkMode control

"call darkMode toggle"
"call darkMode setDark"
"call darkMode setLight"

Modules/IPC/IPCManager.qml

@@ -100,6 +100,19 @@ Item {
     }
   }
 
+  IpcHandler {
+    target: "darkMode"
+    function toggle() {
+      Settings.data.colorSchemes.darkMode = !Settings.data.colorSchemes.darkMode
+    }
+    function setDark() {
+      Settings.data.colorSchemes.darkMode = true
+    }
+    function setLight() {
+      Settings.data.colorSchemes.darkMode = false
+    }
+  }
+
   IpcHandler {
     target: "volume"
     function increase() {