Add rescan_interval to config page

admin-root/config.html

@@ -52,6 +52,10 @@ take effect.
 	  <TD>Extensions</TD>
 	  <TD><INPUT TYPE="TEXT" @READONLY@ NAME="EXTENSIONS" VALUE="@EXTENSIONS@"></TD>
 	</TR>
+	<TR>
+	  <TD>Rescan Interval</TD>
+	  <TD><INPUT TYPE="TEXT" @READONLY@ NAME="RESCAN_INTERVAL" VALUE="@RESCAN_INTERVAL@"></TD>
+	</TR>
       </TABLE>
       <INPUT TYPE="SUBMIT" NAME="SUBMIT" VALUE="Submit">
     </FORM>