Support integrating backend-specific Autoscoper executable & enable CUDA backend

[jcfr]

Build-system updates:

• Removed support for setting Autoscoper_RENDERING_BACKEND option.
• Introduced an explicit AutoscoperM-OpenCL external project.
• Associated Autoscoper "_DIR" variables with the label "Autoscoper_DIRS" allowing to update install and fix-up rules based on the different Autoscoper builds.
• Updated external project variables depending on the project name to use ${proj}_ prefix instead of the hard-coded Autoscoper_ one.

AutoscoperM module updates:

• Updated AutoscoperM module to include a combobox for selecting the rendering backend. The combobox is dynamically populated based on the available Autoscoper executables found in the environment (e.g., autoscoper-CUDA or autoscoper-OpenCL).

Note: The distribution of the CUDA variant of Autoscoper ("autoscoper-CUDA") will be integrated in subsequent commits.

List of Autoscoper updates:

$ git shortlog d476e2cbb..644473784 --no-merges
Jean-Christophe Fillion-Robin (2):
      COMP: Update cutil headers to fix build against SDK without cufft library
      COMP: Ensure Autoscoper inner-build is built with expected CUDA toolkit

[jcfr]

Locally building on the windows factory completes without issue.

Once a clean build & upload of package has been tested manually, this PR will be merged :rocket:

[jcfr]

After running .\SlicerWithSlicerAutoscoperM.exe from the build tree:

---

... but attempting to start either the CUDA or OPEN executable is failing :x: :

[jcfr]

The support for running Autoscoper from a build tree on Windows is expected to be fixed though these pull requests:

• https://github.com/BrownBiomechanics/SlicerAutoscoperM/pull/74
  • itself depending on https://github.com/Slicer/Slicer/pull/7485

[jcfr]

Local testing confirmed that locally packaging the extension on Window and installing it allows to select either the CUDA or OpenCL backend before starting Autoscoper.

[jcfr]

Considering that local testing confirmed that Autoscoper built on Windows with either with the CUDA or OpenCL rendering backend could be executed from an installed SlicerAutoscoperM extension, I am moving forward with the integration :rocket: :white_check_mark:

cc: @amymmorton @bpaniagua @NicerNewerCar