Search, clean up

- Removing references to controller passed in as $controller
- New search response maker
- Article controller now longer passes in reference to itself to the
responseMaker
- New search controller with associated API functionality
- New helper method to get channelId From article object
- New IOC binding for SearchResponseMaker
- New search related routes
- Removing articleRepositoryInterface as no longer required
- Removed references to articleRepositoryInterface from
ArticleRepository
- New search model