Support the import.meta property

Through the `import.meta` property the engine can pass some values to
the module. Currently only the `path` of the script file is exposed.

source/scriptinterface/ModuleLoader.h

@@ -100,6 +100,8 @@ public:
 
 private:
 	// Functions used by the `ScriptContext`.
+	[[nodiscard]] static bool MetadataHook(JSContext* cx, JS::HandleValue privateValue,
+		JS::HandleObject metaObject) noexcept;
 	[[nodiscard]] static JSObject* ResolveHook(JSContext* cx, JS::HandleValue,
 		JS::HandleObject moduleRequest) noexcept;
 	[[nodiscard]] static bool DynamicImportHook(JSContext* cx, JS::HandleValue referencingPrivate,