Make BindGroups take (buffer, offset, size) instead of a buffer view

[Kangz]

Metal, Vulkan, and the sketch WebGPU IDL don't need to create buffer views to set UBOs or SSBOs in bind groups. We should match that, which would also allow removing the concept of buffer views until we introduce texel buffers.

The corresponding WebGPU IDL for reference:

dictionary WebGPUBufferBinding {
    WebGPUBuffer buffer;
    u32 offset;
    u32 size;
};