corporate vita: do not show event memberships.

trello:
https://trello.com/c/dRmMDam1/688-korrektur-der-wingolfitischen-vita
corporate vita: fixing specs.

trello:
https://trello.com/c/dRmMDam1/688-korrektur-der-wingolfitischen-vita
fixing nav path for users.

trello:
https://trello.com/c/dRmMDam1/688-korrektur-der-wingolfitischen-vita
status groups: fixing status workflow group removal brick.

The current status in a corporation has to be unique. Make sure that
the user is not member of two status groups at the same time during a
workflow. Otherwise this might raise errors if another show request is
handled at the same time.