BUG #13842. Fixed state loading for CameraLink.

Fixing logic to load XML state for CameaLinks. The bug was introduced when
cleaning up direct depedencies on "Rendering" for ServerManager/Core. We
overcome the dependency issue by using vtkPVInstantiator to create the
vtkSMCameraLink when needed.

Change-Id: I8cb5d3a8bc32f4646956dfefe02e077a97f87085
Merge topic '13842_fix_camera_link_state_loading' into next

864b9ca BUG #13842. Fixed state loading for CameraLink.