Disambiguate names with role and organisation

When selecting a name from a drop down list, editors need to be sure they are picking the correct person. This change adds a person's organisation and role (if they are available) in the drop down text.

https://www.agileplannerapp.com/boards/173808/cards/5172
rest of the changes look good! this needs to be `Person.includes(:current_roles).all` to save a bunch of `n+1`s.