When I invite someone to join my Space, I can assign them a Role

(User Story, Closed -> Fixed, Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Access Control
Summary: That is, I should make the initial decision about which Role this person has when I am dealing with their membership.
This presupposes that the standard Roles exist.
When Join Space gets implemented, this decision should happen at that point.