Make addressable content types from Prismic available through the Content API and display these in search results.

See on roadmap: https://www.notion.so/wellcometrust/0a1bbf629cd742d2b938260c450ff005?v=9587100363c04d01abe8256c6fa9a02d&p=076df49f41064adabc05ccec75aa8d9f&pm=s