CUDA-related updates and cleanups

[abbradar]

Motivation for this change

1. Update CUDA toolkit to the latest version, make it default;
2. Make a unified config flag cudaSupport which controls whether CUDA support is desired in applications;
3. Update and cleanup various machine learning libraries which make use of CUDA.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

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[abbradar]

Notice that I don't have access to NVIDIA GPU now (My Google Cloud free credit ran empty :D) so it'd be nice to have someone test those changes (I used all of them but some time ago and rebase may have broken things).

[abbradar]

I've managed to make my laptop's hybrid Nvidia to work with CUDA so these changes are mostly tested now. Let's merge this after #29814 lands so that our default Boost plays nicely with new toolkit.