feat(VR): enable SSR

[alandtse]

This is a work in progress and for documentation only.

Issues with VR SSR:

• [x] Black banding which results in line like artifacts in the reflection that are very obvious when moving. See kSSR_RAW below. - Significantly reduced by 0b80c08 combined with updating iterations to 64 for VR (may not be worth the costs). This is actually masking for SSR so should be ignored in water shader to avoid the banding.
• [x] Fog/effect shader effects appear lagged - This appears to be caused by the effects shader running later to update the clouds so we're using kMain_Only_Alpha from the prior frame. In VR you can shake you head much faster than the mouse so while flat also has a disparity, the difference is much smaller and less noticeable. 634a624 (#502)
• [x] Jagged edges - High iterations helps reduce significantly. Set vr to 48 vs 16 flat. 3bd4181 (#502)
• [x] Artifacts if hands block water - Won't fix, this is in vanilla
• [x] Artifacts if too close to water's surface - Using mask for ssr and not using the data should resolve.
• [x] Water shader should ignore SSR mask and pull reflection data from elsewhere. 6ab66af (#502)
• [x] Upscaler/dynamic res support - e7312b2 (#502)
• [x] Fog - Looks like vanilla bug where fog is not rendered in time for SSR. Not related to alpha map. Issue is Fog is applied but requires SSR input. This can't be fixed without another fog application pass.
• [x] Minor eye inconsistencies on edges - f356dbc (#502)

Cleanup tasks:

• [x] Currently does a postpostload manually to enable the hidden setting in VR early enough. Should probably add a general feature for postpostload. - c55e583 (#502)
• [x] Revert commit to make reflections more obvious. 80acf0f30cf5549a440d2482e67225b26662a3d6 - 1e8c2ed (#502)

[alandtse]

This is ready, but should probably handle some of its predecessor PRs first. I also have some second stage prs that should go in too before this.