Quadtree

This is really neat, I've been waiting for a proper HDR10 implementation in Godot for awhile. A couple comments: I think this PR uses a `VK_FORMAT_A2B10G10R10_UNORM_PACK32` / `VK_COLOR_SPACE_HDR10_ST2084_EXT` swapchain. I...

Since it looks like this is getting pretty close, I decided to run it locally for testing. I missed the `hdr_2d` step so that had me confused for a bit,...