gpu: add option "no_compute" to forcibly disable the use of compute shaders

[ruihe774]

See mpv-player/mpv#14163

Also worth noting some GPUs have better performance with fragment shaders than compute shaders. For example my Intel DG2 [Arc A750] on Linux.

[haasn]

It may be better to handle this on the pl_gpu level, by disabling the compute capability outright. Or adding a capability to prefer fragment shaders over compute shaders.

[kasper93]

Related https://code.videolan.org/videolan/libplacebo/-/issues/310 I would prefer some sort of "detection", because while option will allow users to control that, how user can know if they should disable it?

[norinoriko]

Auto-detection wouldn't really benefit people who do get better performance with compute shaders, but want to disable it for other reasons (like power usage). So I still think there's value in exposing such an option to users.