Since we use this for decoding, this adds a dependency to the core
filament renderer which in practice is only used for Vulkan. However
this is a tiny library, so it's simplest just to always include it.
The next PR will add the actual compression / decompression code to
filaflat and filamat. Here are the preliminary results.
102K => 29K aiDefaultMat.filamat
102K => 29K aiDefaultTrans.filamat
21K => 5.0K bakedColor.filamat
22K => 5.2K bakedTexture.filamat
21K => 5.0K depthVisualizer.filamat
40K => 10K groundShadow.filamat
102K => 29K sandboxCloth.filamat
125K => 36K sandboxLit.filamat
126K => 36K sandboxLitFade.filamat
126K => 36K sandboxLitTransparent.filamat
109K => 31K sandboxSubsurface.filamat
21K => 4.9K sandboxUnlit.filamat
21K => 4.9K transparentColor.filamat
Both the "before" and "after" numbers are excluding non-Vulkan targets,
and I also changed our CMakeLists to build filamat instead of inc.
