LibDraw: Introduce (formerly known as SharedGraphics.)

Instead of LibGUI and WindowServer building their own copies of the drawing
and graphics code, let's it in a separate LibDraw library.

This avoids building the code twice, and will encourage better separation
of concerns. :^)

Libraries/LibGUI/GDesktop.h

@@ -3,7 +3,7 @@
 #include <AK/AKString.h>
 #include <AK/Badge.h>
 #include <AK/Function.h>
-#include <SharedGraphics/Rect.h>
+#include <LibDraw/Rect.h>
 
 class GWindowServerConnection;