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