Add a search interactor.
Relocate the search request json fixture.

New location is better suited to having different formats of search response.
Add a content service repository for search.

Munges the response into the same format that we picked for the public website responses.
Adapt the core initializer to use the content service search repository.
Add a fake repository for testing search.
Implement the search controller
Implement the search results page and plumb in the search box.
Move some of the repeated declaration in page objects into the base class.
Update / add page objects for search results.
Add a feature for search behaviour.
Add a decorator for search results.