Libraries: Create top level directory for libraries.

Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.

Libraries/LibC/sys/ioctl_numbers.h

@@ -0,0 +1,14 @@
+#pragma once
+
+enum IOCtlNumber {
+    TIOCGPGRP,
+    TIOCSPGRP,
+    TCGETS,
+    TCSETS,
+    TCSETSW,
+    TCSETSF,
+    TIOCGWINSZ,
+    TIOCSCTTY,
+    TIOCNOTTY,
+    TIOCSWINSZ,
+};