chore: import upstream snapshot with attribution

tools/quantization/quantized.cpp

@@ -0,0 +1,16 @@
+//
+//  quantized.cpp
+//  MNN
+//
+//  Created by MNN on 2019/07/01.
+//  Copyright © 2018, Alibaba Group Holding Limited
+//
+
+#include <fstream>
+#include <sstream>
+#include <string>
+#include "calibration.hpp"
+
+int main(int argc, const char* argv[]) {
+    return quant_main(argc, argv);
+}