Explicit upload heap management

[sherief]

I'd like to create queues with an explicit upload heap provided that I allocate and control. I understand I'll be giving up the heap and its entire VA space to the queue, but right now to do accounting for this heap and its VA range (for, say, Aftermath / DRED post mortem debugging) I need to wrap the entire D3D12 device uses a-la Reshade then capture all upload heaps going out.

This is far from ideal and it makes the road to stable, high performance apps much higher friction than needed.