Add AAIB Reports to Rummager on publish

In order to expose AAIB Reports in search, we need to send the documents
to Rummager when publishing.
Rename specialist_document_path to cma_case_path

With moving away from SpecialistDocument being referenced throughout the
App, we've renamed specialist_document_path to be cma_case_path. This
also allows us to refactor the steps in the Cukes to take a document
type in order to build the paths.
Testing AAIB Report publishing workflow

With the addition of publishing AAIB reports to rummager, we need to
test this workflow.
Allow withdrawal of AAIB reports

Also testing withdrawal workflow.
Merge pull request #163 from alphagov/add-aaib-reports-to-rummager

Add aaib reports to rummager