Remove old CUDA toolkits (and corresponding CuDNN versions).
- Not supported by upstream anymore.
- We do not use them in nixpkgs.
- We do not test or actively maintain them.
- Anything but ancient GPUs is supported by newer toolkits.
Fixes#107131.
Since CUDA is unfree, we won't actually use this when testing Nixpkgs
officially. But I want to include this as they are useful for users of
Nixpkgs trying to set up / debug a CUDA environment.
