A small icon and a placeholder mesh are displayed at the location of
the lights and cameras in the scene, to provide a way to see and
interact with them.
Change-Id: I1f90fce77a643cab2c3fda3ee2105af53dea57a9
Task-number: QDS-1177
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>