Increase all ajax calls to 5 seconds

The default is 2 seconds and this will mean that we are halving traffic
for these ajax calls which can only be good for trying to limit queries
on the database.

I think the user impact on this will likely not be noticable.

Debatable whether we should up them all even further to 10 seconds but
this is definitely a quick although maybe small win.

app/templates/components/ajax-block.html

@@ -1,4 +1,4 @@
-{% macro ajax_block(partials, url, key, interval=2, finished=False, form='') %}
+{% macro ajax_block(partials, url, key, interval=5, finished=False, form='') %}
   {% if not finished %}
     <div
       data-module="update-content"