Integrate Edit3D view into Creator

Edit3D view is now a tab alongside Form Editor.
Buttons were moved to a Creator side task bar on Edit 3D view.

Change-Id: Ia06107e4f855ba512ffea3e628a61558894e800e
Fixes: QDS-1570
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/designmodewidget.cpp

@@ -31,6 +31,7 @@
 #include "qmldesignerplugin.h"
 #include "crumblebar.h"
 #include "documentwarningwidget.h"
+#include "edit3dview.h"
 
 #include <texteditor/textdocument.h>
 #include <nodeinstanceview.h>