misc: include current date/time in statistics PDF (#8917)

data/print-html-as-pdf.js

@@ -20,6 +20,11 @@ page.open(system.args[1], function() {
     $('div#main-content > h2').css({
             'border-bottom': '1px solid #666',
             'font-weight': 'bold'});
+    var date = $('<p>' + new Date().toLocaleString() + '</p>').appendTo('div#main-content');
+    date.css({
+            'position': 'absolute',
+            'top': '2ex',
+            'right': '1em'});
   });
   page.render(system.args[1] + '.pdf');
   phantom.exit();