Show the backup menu entry also on the index_configure.html page

sd-card/html/index_configure.html

@@ -38,6 +38,7 @@
     <li class="dropdown">
 	<a href="javascript:void(0)" class="dropbtn">System</a>
 	<div class="dropdown-content">
+	    <a href="#"onclick="document.getElementById('maincontent').src = '/backup.html';">Backup/Restore</a>
 	    <a href="#"onclick="document.getElementById('maincontent').src = '/ota_page.html';">OTA Update</a>
 	    <a href="#"onclick="document.getElementById('maincontent').src = '/fileserver/log/message/?readonly=true';">Log Viewer</a>      
 	    <a href="#"onclick="document.getElementById('maincontent').src = '/reboot_page.html';">Reboot</a>