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/LibHTML/Frame.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include <LibHTML/DOM/Document.h>
-#include <SharedGraphics/Size.h>
+#include <LibDraw/Size.h>
 
 class Frame {
 public: