cuda-python: Support CUDA 12

[jakirkham]

Depends on issue ( conda-forge/staged-recipes#21382 )

[bdice]

We specifically need nvrtc and cudart per this comment: NVIDIA/cuda-python#43 (comment)

Tracking those:

• Adding cuda-cudart staged-recipes#21723
• Adding cuda-nvrtc recipe staged-recipes#21951

[leofang]

@bdice I actually don't understand why cudart is listed here. CUDA Python reimplemented cudart instead of dlopen'ing libcudart. I still think nvrtc is the only blocker.

[bdice]

@leofang Let's keep that discussion on the existing issue NVIDIA/cuda-python#43. I'd like to use what has been agreed upon there. It's already vastly smaller than depending on the entire cuda-toolkit so I'm satisfied with the outcome.