Allow departments to contain people that are not users

[inghamn]

For some kinds of issues, it would be useful to have CRM send emails to an outside company and autoclose the ticket. To do this, we want to be able to assign non-user people to a department, so they can be associated with the category.

For example:
Scooter and Bike Share issues should be forwarded to the appropriate person in the respective company. We want to have this person set as the default person for the category, rather than a person who is a city employee.