add map report files download link

components/DownloadReport.js

@@ -0,0 +1,13 @@
+import Link from "next/link";
+
+function DownloadReport({ URL }) {
+  return (
+    <p>
+      <Link passHref href={URL}>
+        <button>下载报告</button>
+      </Link>
+    </p>
+  );
+}
+
+export default DownloadReport;