(updated) GPU fluid dynamics

[vale vessel]

thanks to the dev team for making it so easy in GD4, and smoothing over so much of Vulkan's verbosity

[vale vessel]

I ended up using it as part of a fluid simulation on a rotating sphere! here's the Kelvin-Helmholtz instability, although you don't see many small eddies because they're quickly diffused to below the size of the grid I'm using