Loader: Add a GetFileType method to get the type of a loaded file

src/core/loader/loader.h

@@ -131,6 +131,12 @@ public:
     AppLoader(FileUtil::IOFile&& file) : file(std::move(file)) { }
     virtual ~AppLoader() { }
 
+    /**
+     * Returns the type of this file
+     * @return FileType corresponding to the loaded file
+     */
+    virtual FileType GetFileType() = 0;
+
     /**
      * Load the application
      * @return ResultStatus result of function