Make some refactors for name mangling and encapsulation.

13/mangler.hpp

@@ -0,0 +1,9 @@
+#pragma once
+#include <string>
+#include <map>
+
+struct mangler {
+    std::map<std::string, int> occurence_count;
+
+    std::string new_mangled_name(const std::string& str);
+};