I should be able to Give a Space to a new Owner

(User Story, To be Fixed , Priority: Critical, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Access Control
Summary: This is needed for the Arisia project, so that the Space can be given to the EBoard.
This would be easy, except that this is really an offer: I can offer the Space to somebody. They must get a Notification about that. They can then accept or decline the offer. The offerer should get a Notification when it is accepted or declined.
The offerer must be able to suggest the Role(s) that they would like to have in the new Space. The receiver can, as part of accepting, choose which Role to actually give them, with the suggestion as the default. But it is strictly the Receiver's decision.