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/GDirectoryModel.cpp

@@ -4,7 +4,7 @@
 #include <LibCore/CDirIterator.h>
 #include <LibCore/CLock.h>
 #include <LibGUI/GPainter.h>
-#include <SharedGraphics/GraphicsBitmap.h>
+#include <LibDraw/GraphicsBitmap.h>
 #include <dirent.h>
 #include <grp.h>
 #include <pwd.h>