Simple advert format test bed

This gives us a basic system to deliver simple HTML adverts, Eg.

 http://localhost:9000/commercial/jobs
 http://localhost:9000/commercial/soulmates
 http://localhost:9000/commercial/...

As each one evoles in to something more complex we can split in to a seperate controller, as with travel offers.
One template per advert
Make the templates distinct from each other
Merge pull request #2037 from guardian/simple-adverts

Simple adverts