Add variable to CMAKE

[martinfantini]

In the case the library is compiled with VTK the visualization variable is:

set (OpenCASCADE_Visualization_LIBRARIES TKService;TKV3d;TKOpenGl;TKMeshVS;TKIVtk)

And now there is a Visualization variable with VTK and without VTK:

set (OpenCASCADE_Visualization_VTK_LIBRARIES TKService;TKV3d;TKOpenGl;TKMeshVS;TKIVtk)
set (OpenCASCADE_Visualization_LIBRARIES TKService;TKV3d;TKOpenGl;TKMeshVS)

[dpasukhi]

Dear @martinfantini

Thank you for your patch. To proceed with integration, please complete signing CLA process:
The links: Contribution Guide
Or https://dev.opencascade.org/get_involved

In case if you already have signed CLA, please share ID that OCCT team shared with your by email after accepting of CLA.

[martinfantini]

@dpasukhi I sign the CLA and send to you.

[dpasukhi]

CLA ID: 1135