LibHTML: Add ResourceLoader to support protocol-agnostic URL loading

We now support loading both file:// and http:// URLs. Feel free to
visit http://www.serenityos.org/ and enjoy the fancy good times. :^)

Libraries/LibHTML/ResourceLoader.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <AK/Function.h>
+#include <AK/URL.h>
+
+class ResourceLoader {
+public:
+    static ResourceLoader& the();
+
+    void load(const URL&, Function<void(const ByteBuffer&)>);
+
+private:
+    ResourceLoader() {}
+};