Add schema for drug safety updates
Adding model and validator for DSU
DRY up routes
Add DSU to the Wiring
Add formatters for DSU
Add permission check for DSU
Add controllers for DSU
Add observers and services for DSU
Add DSU views and routes
Testing DSU workflow for MHRA editors

Also removing the user_can_edit_format_name methods as now we can use
current_user_can_edit? method instead.
Merge pull request #230 from alphagov/add-drug-safety-updates

Add drug safety updates
Restrict allowed image hosts

This prevents images not hosted by us from being included in content on GOV.UK
by content editors or an attacker who has gained control of an editor's
account. Such images could be altered to something malicious (or a trollface)
at the whim of the website owner or an attacker who gains control of that
domain.

This is provided by version 19.0.0 of govuk_content_models.
Allow FinderSchema to humanize values
Allow DocumentViewAdapter to humanize attributes
Make show views render humanized metadata
Make therapeutic_are a multi select
Merge pull request #233 from alphagov/bug/multi-select-therapeutic-area

Multi select therapeutic area
Copy and paste fail on DSU attachment controller
Merge pull request #234 from alphagov/bugfix/dsu-attachments

Copy and paste fail on DSU attachment controller
Merge pull request #232 from alphagov/restrict_allowed_image_hosts

Restrict allowed image hosts