LibGL+LibGPU+LibSoftGPU: Implement matrix stack per texture unit

Each texture unit now has its own texture transformation matrix stack.
Introduce a new texture unit configuration that is synced when changed.
Because we're no longer passing a silly `Vector` when drawing each
primitive, this results in a slightly improved frames per second :^)

Userland/Libraries/LibGPU/Enums.h

@@ -120,7 +120,7 @@ enum StencilTestFunction {
     NotEqual,
 };
 
-enum TexCoordGenerationCoordinate {
+enum TexCoordGenerationCoordinate : u8 {
     None = 0x0,
     S = 0x1,
     T = 0x2,