LibGfx: Implement YUV->RGBA color conversion for CPU painting

Using the Rust yuv crate, eagerly convert from YUV to RGBA on the CPU
when a GPU context is unavailable.

Time spent converting an 8-bit YUV frame with this crate is better than
libyuv on ARM by about 20%, and on x86 with AVX2, it achieves similar
numbers to libyuv.

Libraries/LibGfx/YUVData.h

@@ -9,6 +9,8 @@
 #include <AK/Error.h>
 #include <AK/FixedArray.h>
 #include <AK/NonnullOwnPtr.h>
+#include <AK/NonnullRefPtr.h>
+#include <LibGfx/Forward.h>
 #include <LibGfx/Size.h>
 #include <LibMedia/Color/CodingIndependentCodePoints.h>
 #include <LibMedia/Subsampling.h>
@@ -42,6 +44,8 @@ public:
     Bytes u_data();
     Bytes v_data();
 
+    ErrorOr<NonnullRefPtr<Bitmap>> to_bitmap() const;
+
     SkYUVAPixmaps make_pixmaps() const;
 
     void expand_samples_to_full_16_bit_range();