Integration of the Virtual Reality

See merge request iMSTK/iMSTK!243

The simulation can now be set to either instantiate:
  - A regular simulation using vtkRenderWindow
  - A VR simulation using vtkOpenVRRenderWindow

To do so, the simulation manager can be set to be a VR simulation
when initialized. The default comportment will be a regular simulation.

BUG: Use proper writer for VTU file

See merge request !242

COMP: Allow build of projects depending on iMSTK updating the config file

See merge request iMSTK/iMSTK!241

ENH: Add Orange color

See merge request iMSTK/iMSTK!240

Suggested-by: Alexis Girault <alexis.girault@kitware.com>

This is needed for the VROrthognathic/OrthognathicTrainer project.

This commit adds missing dependencies to iMSTKConfig file.

Assimp was originally introduced in f859365b (ENH: Added Assimp support
to improve mesh reading)

glm became a mandatory dependency in 54a68c1f (ENH: added decals to the
Vulkan renderer)

COMP: Support build with BUILD_EXAMPLES and BUILD_TESTING set to OFF

See merge request iMSTK/iMSTK!236

COMP: Update external projects to use CMAKE_CACHE_ARGS

See merge request iMSTK/iMSTK!238

Unless option have to be passed using the command line, this is the
recommended approach to pass options. It avoids "command line length issues".

COMP: Fix compilation error in VulkanTextureDelegate

See merge request iMSTK/iMSTK!233

Surface mesh fixes and decals

See merge request iMSTK/iMSTK!224

CLEANUP: added ability to expand surface meshes, abstracted interactor, and fixed transforms in Vulkan renderer

Changed to pass the shared_ptr by reference.

See merge request iMSTK/iMSTK!231

Add relaxation solvers

See merge request iMSTK/iMSTK!230

Simplifies graph printing format.

Add graph class with graph greedy coloring algorithm

See merge request iMSTK/iMSTK!228

Clears bug and refactor mesh-mesh collision

See merge request iMSTK/iMSTK!227