[WIP] Add more configuration options and dependency path autoconfiguration for GPU Tracking Standalone build

[davidrohr]

@MichaelLettrich : First attempt to improve my CMake for the GPU Standalone build:

• It now requires CMake 3.14 (since I have been using 3.14 syntax, as you figured out...)
• It should auto-detect ms_gsl.
• Disabling the standalone event display in the config file should work now, also for Vc / fmt / OpenMP.
• Disabling ROOT doesn't work right now (Still works with the old makefile). It is too deeply integrated in our CMake. Perhaps I'll reevaluate next time I have remote access to a GPU machine without ROOT, but for now this is not needed.
• For CUB / FMT, you'll still need to provide CMake options -Dfmt_DIR=[SW_DIR]/fmt/latest/lib64/cmake/fmt/ -Dcub_ROOT=.... (Unfortunately, I cannot autodetect them, since our alidist recipes do not set environment variables for them, and I don't want to mess with the recipes for my standalone tool... If they are installed systemwide, they should be detected correctly.)
• The rest I just tested in alidock, and it worked for me.

[MichaelLettrich]

Does that mean we should bump CMake as well?

[davidrohr]

We will globally bump CMake to 3.15 once that is out I think because the next FairROOT/DDS will need the new CMake.

[davidrohr]

@Barthelemy : It seems this QC test breaks the O2 CI for my PR:
5/17 Test #6: testTaskInterface ................***Timeout 30.06 sec