Make 3D objects pickable

Mark 3D objects implicitly pickable upon initialization so that they
receive mouse clicks without having to declare the pickable property
in qml.

Task-number: QDS-1124
Change-Id: Ib8ec5415097c1a9bf57b8965a3fca0c3665f3732
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

share/qtcreator/qml/qmlpuppet/qml2puppet/instances/quick3dnodeinstance.h

@@ -44,6 +44,8 @@ public:
     ~Quick3DNodeInstance() override;
     static Pointer create(QObject *objectToBeWrapped);
     void setHideInEditor(bool b) override;
+    void initialize(const ObjectNodeInstance::Pointer &objectNodeInstance,
+                    InstanceContainer::NodeFlags flags) override;
 
 protected:
     explicit Quick3DNodeInstance(QObject *node);