Add pytorch on Windows related info to faqs

[traversaro]

We took some time with @giotherobot to debug this error today:

OSError: [WinError 182] The operating system cannot run %1. Error loading "D:\miniforge\envs\robsub\Lib\site-packages\torch\lib\fbgemm.dll" or one of its dependencies.

that we had when trying to load import torch. This was because we had both openmp and intel-openmp installed in your conda environment.

This may not be the perfect place, but we owe humanity to put this information somewhere reachable.

See conda-forge/conda-forge-pinning-feedstock#1359 for more infomation.

xref:

• Possible to build flang / libflang with intel-openmp, rather than openmp? conda-forge/flang-feedstock#26
• intel-openmp should conflict orther impls conda-forge/intel_repack-feedstock#59
• Conflict between intel-openmp and llvm-openmp ContinuumIO/anaconda-issues#13146
• File conflict between llvm-openmp (and old openmp) and intel-openmp conda-forge/conda-forge.github.io#1597