QmlDesigner: Integrate MCU example to welcome page

Task: QDS-3618

Change-Id: I65f6dc4ebd3a2f0ca97838ccc89e7054eb083941
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/studiowelcome/qml/welcomepage/ExamplesModel.qml

@@ -67,4 +67,11 @@ ListModel {
         thumbnail: "images/progressbar_demo.png"
         displayName: "Progress Bar"
     }
+
+    ListElement {
+        projectName: "washingMachineUI"
+        qmlFileName: "washingMachineUI.qml"
+        thumbnail: "images/washingmachinedemo_thumbnail.png"
+        displayName: "Washing Machine"
+    }
 }