The goal of this WS is to return data that will be displayed in the bulk change form (was done previously in rail in views/issues/_bulk_change_form.html.erb).
As it's purely ui oriented, it should be a private WS.
The parameters should be exactly the same as ones defined in api/issues/search WS (expect pagination that should be set to the max values, 500). The only required permission is to be authenticated.
The result could looks like :