SSAO/SSGI followup tracking issue

SSAO got merged in #7402, but there's still a lot we can do better.

## Performance
- [ ] Faster depth->world position (see reverted code)
- [ ] Render at half resolution and use a bilateral upsample
- [ ] F16 math (missing naga-wgsl support https://github.com/gfx-rs/wgpu/issues/4384)
- [ ] Faster depth mipchain creation (https://github.com/GPUOpen-Effects/FidelityFX-SPD) (wgpu/naga does not currently support subgroup ops)

## Quality
- [ ] Replace the spatial denoiser with a combined spatial+temporal denoiser, similar to bevy_solari's
- [ ] Try interleaved gradient noise or tellusim's spatiotemporal blue noise for sampling
- [ ] Bent normals
- [ ] Better multibounce approximation (https://drive.google.com/file/d/1SyagcEVplIm2KkRD3WQYSO9O0Iyi1hfy/view)
- [ ] Configurable parameters/heuristics

## Platform Support
- [x] SSAO currently does not work on DirectX12 due to issues with wgpu and naga:
* https://github.com/gfx-rs/wgpu/pull/3798
* https://github.com/gfx-rs/naga/pull/2353 (we have a work-around for this issue in the SSAO shaders atm)
- [ ] SSAO currently does not work on WebGPU because r16float is not a valid storage texture format https://gpuweb.github.io/gpuweb/wgsl/#storage-texel-formats. We can fix this with a fallback to r32float.

## Recent Algorithm Advancements
- [x] Visibility bitmask (https://cdrinmatane.github.io/posts/ssaovb-code/, https://link.springer.com/article/10.1007/s00371-022-02703-y, https://cdrinmatane.github.io/posts/cgspotlight-slides/)
- [ ] Screen space diffuse lighting (https://github.com/Patapom/GodComplex/blob/master/Tests/TestHBIL/2018%20Mayaux%20-%20Horizon-Based%20Indirect%20Lighting%20(HBIL).pdf)