Add AAIB Reports schema
Add AAIB Reports schema

In order to expose AAIB reports in search, we've added the schema for
the facets on the reports.

Trello ticket:
https://trello.com/c/X4vUOJzE/203-add-aaib-reports-into-search-results-2

alphagov/rummager,theodi/rummager,alphagov/rummager,theodi/rummager