Activity conveners group (#1651)

* Rename activity group list

* Add how to contact all conveners

Get rid of anachronistic WG page (which was invisible anyway, thanks
to a redirect)

* Remove unneeded text

Author: graeme-a-stewart

calendar.md

@@ -8,8 +8,8 @@ The HSF [Community Calendar](https://calendar.google.com/calendar/embed?src=e4v3
 can be edited by people in the following Google Groups:
 
 - [HSF Steering Group](https://groups.google.com/forum/#!forum/hsf-steering)
-- [HSF Activity Area Conveners](https://groups.google.com/forum/#!forum/hsf-wg-conveners)
-- [HSF Calendar Editors Group](https://groups.google.com/forum/#!forum/hsf-calendar-editors) Google Groups.
+- [HSF Activity Area Conveners](https://groups.google.com/forum/#!forum/hsf-activity-conveners)
+- [HSF Calendar Editors Group](https://groups.google.com/forum/#!forum/hsf-calendar-editors)
 
 The most straight forward way to do this is to 
 

what_are_WGs.md

@@ -47,3 +47,8 @@ but are kept for reference:
   <li> <a href="{{ activity.url }}">{{ activity.title }}</a></li>
 {% endfor %}
 </ul>
+
+## Activity Area Contacts
+
+Each activity area lists its conveners and gives contact details. In addition,
+all conveners can be contacted at `hsf-activity-conveners AT googlegroups.com`.