地理行政区域json 最新的2019年的。有详细的 三级区域。 编码为六位的 行政编码作为code 110000 等等 如：[{"code":"110000","name":"北京市","children":[{"code":"110100","name":"市辖区","children":[{"code":"110101","name":"东城区","level":2},{"code":"110102","name":"西城区","level":2},{"code":"110105","n