Clicking an object in the 3D object selection view, selects it in the
creator side. Multiselection (i.e. Ctrl+click) is not implemented yet.
Also selected object is not highlighted in the view yet.
Task-number: QDS-1124
Change-Id: I0b10162539ecedc40ed117896e385975c52b04a9
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>