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/LibHTML/DOM/Text.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <AK/AKString.h>
+#include <LibHTML/DOM/Node.h>
+
+class Text final : public Node {
+public:
+    explicit Text(const String&);
+    virtual ~Text() override;
+
+    const String& data() const { return m_data; }
+
+private:
+    String m_data;
+};