Append related links to quick links

https://www.agileplannerapp.com/boards/105200/cards/6149

Having discussed design on this, the approach is to see how a mixed list of quick links and related contacts works initially. So... 

- Provide convenience method for related links
- Update view for design consistency with other related links


![screenshot - 011014 - 17 17 48](https://cloud.githubusercontent.com/assets/93511/4478591/be8415c4-4986-11e4-8411-642b84f94a8e.png)


NB: this is a rework of https://github.com/alphagov/contacts-frontend/pull/15