ffmpeg Vulkan Video API/decoder  and CUDA

### Discussed in https://github.com/PyAV-Org/PyAV/discussions/1276

<div type='discussions-op-text'>

<sup>Originally posted by **bhack** February 15, 2024</sup>
Is it possible to use [FFMPEG Vulkan decoder](https://trac.ffmpeg.org/wiki/HWAccelIntro#Vulkan) and then [access with cuda](https://github.com/FFmpeg/FFmpeg/blob/master/libavutil/hwcontext_vulkan.c#L3572) using PyAV?</div>