Add button for creating forum thread draft from event detail

TODO: Allow RIGS to ingest POST requests sent from the forum on new posts in RIG info to link up the forum thread

RE https://forum.nottinghamtec.co.uk/t/rigs-discourse-integration/15592/21

RIGS/templates/partials/event_details.html

@@ -77,6 +77,15 @@
                 <dt class="col-sm-6">PO</dt>
                 <dd class="col-sm-6">{{ object.purchase_order }}</dd>
             {% endif %}
+
+            <dt class="col-6">Forum Thread</dt>
+            {% if event.forum_thread %}
+            <dd class="col-6"><a href="{{event.forum_thread}}">{{event.forum_thread}}</a></dd>
+            {% else %}
+            <a href="{% url 'event_thread' event.pk %}" class="btn btn-primary" title="Create Forum Thread"><span
+            class="fas fa-plus"></span> <span
+            class="hidden-xs">Create Forum Thread</span></a>
+            {% endif %}
         </dl>
     </div>
 </div>