Hack around kaminari's inability to handle generic controllers.

This is a TEMPORARY fix to allow pagination to work until we fix pagination properly.

Kaminari, internally, uses url_for(controller:, action:) to generate routes. See
https://github.com/amatsuda/kaminari/blob/adca9b25b4d3fefcb12552e939d7262eb86a3ec0/lib/kaminari/helpers/tags.rb#L30

In specialist-publisher, we have a route for each report (aaib_reports_path) which all use the same controller and action. When Kaminari calls `url_for(controller: "abstract_documents", action: "index")`, the first matching
result in routes.rb is returned, which is AAIB reports. So the CMA cases pagination links are linking to /aaib-reports?page=2.

Override how page_url_for(page) works in specialist-publisher to instead take an extra parameter of document_type and call the correct routing helper using send. Ugh.

Better fixes for this are probably:

1. Switch pagination libraries to something which allows explicit path overriding.
2. Use wrapper controllers -- one for each format -- which inherit from `AbstractDocumentsController`
3. Make a pull request to kaminari to fix this.
4. Disable pagination.