Amalgamated user prefs, full page ads

- Updated to provide a single endpoint to allow for the setting of
channel, sub-channels, categories and districts from the user
preference screen.
- Articles at category level now return a 4th adverts marked as ‘full
page’
- User preferences now accept a GET to retrieve all channel and
district data as well as a POST to set the inEnabled & isPromoted flags
against each content item
Sponsor updates
Re-worked UserPreferenceResponseMaker
Merge branch 'user-prefs-v2' into dev
Bug fix - SponsorResponder