1) Fix #16969 by using GL_UNPACK_IMAGE_HEIGHT instead of the extension
in vtkVolumeTexture
2) Remove duplicates from architecture list
3) Ensure we have at least one architecture to compile for
4) Add missing modules to toolchain: vtkIOXML & vtkRenderingVolumeOpenGL2
5) Add additional module for LOD actors:vtkRenderingLOD
6) Correct check to set VTK_RENDERING_BACKEND to OpenGL2
7) Do not cross-compile for simulators if none are defined
8) Get rid of VTK_DEVICE_LIBS and VTK_SIMULATOR_LIBS to directly populate
VTK_GLOB_LIBS based on what libraries are being built
9) Replace VTK_DEVICE_DEPENDS by IOS_ARCHITECTURES and populate based on
what libraries are being built
10) Replace hardcoded vtk-ios-device-arm64 by first ios architecture in the
architecture list to copy existing headers
11) Use list instead of set when possible (not for files in VTK_GLOB_LIBS
since items should not be separated by ; to run the GLOB)
12) Correct comments in MakeFramework.cmake.in