Implementation of StorageBuffer on WebGPU

[mvaligursky]

related to #6009

• implementation of the StorageBuffer class, to be used with WebGPU's Compute for read/write data.

intended public API

StorageBuffer.constructor(device, byteSize, bufferUsage);
StorageBuffer.destroy();

// clear part of the buffer to 0
StorageBuffer.clear(offset, size);

// async read of the GPU buffer
StorageBuffer.read(offset, size, allocatedTypeArray) : Promise<ArrayBuffer>;

// async upload (not implemented yet, follow up PR)
StorageBuffer.write(data, offset);

• Compute now handles StorageBuffer as input / output. This will be slightly expanded in the follow up PRs (for example read-only buffer)
• new example which demonstrate how to create a compute shader that generates a histogram, from the rendered image, downloads the results to CPU and renders it using lines. This is not the most performant implementation, as it requires async data download to the CPU, but this example demonstrates exactly that case, where a result of compute is needed on CPU. We'll have another example where compute generated storage buffer gets consumed by the GPU directly vertex of fragment shader).

[kpal81xd]

This array format seems v messy maybe replace with an object with keys to describe each array?

[mvaligursky]

yeah good suggestion, but outside of the scope of this PR.

[willeastcott]

Approving with minor comments. Nice! 👏