QmlDesigner: Re-add transform.png file

This re-adds file transform.png, removed in commit
9e1125d4.

The icon is still referenced in source code.

src/plugins/qmldesigner/components/formeditor/formeditor.qrc

@@ -4,6 +4,7 @@
     </qresource>
     <qresource prefix="/icon/tool">
         <file>anchor.png</file>
+        <file>transform.png</file>
     </qresource>
     <qresource prefix="/icon/layout">
         <file>snapping.png</file>