ZA added detail to constituency pages and additional links in site navigation

This commit includes a few display changes:
* A person's contact details are now included on a constituency page (a change requested by PMG). The position kind (e.g. constituency contact, administrator) is also added to the template -  which begins to address issue #1183.
* Links to two new static pages are added to the about menu.
* A link to the source data static page is added to the disclaimer in the footer of the site.