Wrap Finder formats in a Dropdown if GDS Editor

As GDS Editors, the amount of Finders was breaking the header
navigation. Now, we wrap the Finders in dropdown tags if the user is
from GDS. We also display the name of the current finder in the dropdown
if one is selected.

Also, adding a new route and permission check in the view requires
adding a new item in the hash in the application controller.
Merge pull request #299 from alphagov/nav-collapse-with-lots-of-finders

Wrap Finder formats in a Dropdown if GDS Editor
Inject document type not a pre-scoped model to repositories.

In each case in the `RepositoryRegistry`, `specialist_document_editions` was
just a pre-scoped `SpecialistDocumentEdition` by document type.

I have refactored this scoping to happen within the Repository, as every place
that a repository was being used was being scoped by document type, and there
is no scenario we have encountered where this is not the case.

Further, part of the point of using the repository pattern is to concrete all
datastore access/operations inside the repository, so having this occur outside
the repository smelled a little to me.

This will provide further benefits when we introduce a Single Source of Truth
to list the available document types, making it much easier for us to use that
Single Source of Truth in future to simplify repository access.
Update README to account for new menu style

776446d9c5d9123d86513fa847539ee1c44c13f8 Changed how the menu was generated.
Update the readme to take this into account.
Concrete document factories in a single location

* We weren't using non-validatable entity factories anywhere.
* Logic for creating documents based on format was split into different locations.
* The edition_factory used by SpecialistDocument was always `SpecialistDocumentEdition.new`.
* The generic concept of "entity" actually referred to documents.

Further, by concreting the specifics of how we build each document format in a
single location, we can see the common behaviour better, which will assist us
in further refactoring when we introduce a Single Source of Truth about which
document formats we deal with.
Merge pull request #304 from alphagov/remove-scoped-editions-from-repository-registry

Inject document type not a pre-scoped model to repositories.
Merge pull request #305 from alphagov/simplify-factory-registries

Concrete document factories in a single location
Update README post entity-factory refactor.
Merge pull request #306 from alphagov/update-readme-for-finders-array

Update README to account for new menu style
MHRA doc formats have pluralised URLs

MHRA doc formats are singular in the frontend, but need to be plural in
the editor.
Merge pull request #308 from alphagov/pluralise-mhra-doc-formats

MHRA doc formats have pluralised URLs
Merge pull request #307 from alphagov/update-readme-for-entity-factory-refactor

Update README post entity-factory refactor.
Remove stale service registries and refactor the repository registry

* Refactor repository registry: The difference is only the document type.
  Everything should now use `RepositoryRegistry.new.for_type("document_type")`
* AttachmentServiceRegistry and ServiceRegistry classes were no longer used
  since they're built in the abstract by passing in a document type (in
  `app/lib/specialist_publisher.rb`) now.
Merge pull request #309 from alphagov/remove-specific-repository-methods

Remove stale service registries and refactor the repository registry
Add importer and auto-publisher: medical alerts
Add importer and auto-publisher for RAIB reports
Correct naming: remove the word "reports"

We're not referring to drug safety updates as reports elsewhere.

Also, "Loading all draft DSU reports" reads as:
"Loading all draft drug safety update reports"

A little clunky.
Merge pull request #311 from scraperwiki/dsu-import-typo-fix

Correct naming: remove the word "reports"
Merge pull request #300 from scraperwiki/import-and-publish-drug-and-device-alerts

Add importer and auto-publisher: medical alerts
Merge pull request #310 from scraperwiki/import-raib-reports

Add importer and auto-publisher for RAIB reports