First pass at using puffin to display the query results

[Gonkalbell]

Here's a first pass at a way to display the GpuTimerQueryResult in puffin. This only depends on the base puffin crate, not puffin_egui or puffin_http. I added puffin_http as a dev dependency to the example since it's not as invasive of a change as using egui.

This current approach assumes you use a different puffin::GlobalProfiler for wgpu than for CPU threads. I'm not the biggest fan of this approach, and I'd prefer to pretend that the WGPU Queue is just like any other CPU thread, and show them all in the same profiler window. However, the fact that we may need to wait several frames for timer results from the GPU makes this difficult.

[Wumpf]

sorry for the delay in review. Hoping to give this a spin by the end of the week!