LibWeb: Add CDATASection

Not used for anything currently other than exposing it on the Window
object. This allows Web Components Polyfills to patch its prototype.

Userland/Libraries/LibWeb/DOM/CDATASection.cpp

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2022, Luke Wilde <lukew@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/DOM/CDATASection.h>
+
+namespace Web::DOM {
+
+CDATASection::CDATASection(Document& document, String const& data)
+    : Text(document, NodeType::CDATA_SECTION_NODE, data)
+{
+}
+
+CDATASection::~CDATASection()
+{
+}
+
+}