euscanwww: Refresh query logic and task queue split in chunks

Added the needed logic for running refresh queries from the web
interface.

Added a simple function to tasks.py that takes an iterable of arguments
and a task and launches many subtasks formed by 32 tasks each (for not
having a huge amount of tasks launched at the same time)

Signed-off-by: volpino <fox91@anche.no>

euscanwww/djeuscan/templates/euscan/package.html

@@ -140,8 +140,8 @@
 
 <script type="text/javascript">
   $(".refresh-button").click(function() {
-    var url = "{% url "apply_task" "djeuscan.tasks.scan_upstream_task" %}";
-    $.post(url, {query: $(this).data("package")}, function() {
+    var url = "{% url "refresh_package" "x/x" %}";
+    $.post(url.replace("x/x", $(this).data("package")), function() {
       alert("Submitted!");
     });
   });