In analysis controller, allow opening tabs in the background.

This is useful when the jury wants to look at all problem stats after
import, and it was unnecessarily prevented by our use of JS to make the
whole row clickable.

webapp/templates/jury/analysis/contest_overview.html.twig

@@ -25,8 +25,12 @@
 </style>
 <script>
 $(function() {
-    $(".clickable-row").click(function() {
-        window.location = $(this).data("href");
+    $(".clickable-row").click(function(e) {
+        if (e.ctrlKey) {
+            window.open($(this).data("href"), '_blank');
+        } else {
+            window.location = $(this).data("href");
+        }
     });
     $('[data-bs-toggle="popover"]').popover({
       trigger: 'hover',