Load last now valid group membership of user to get a nice breadcrumb
Navigation for users should start at last valid group of first corporation
Call sort_by( valid_from ) with default value to prevent nil
Flush cache also on destroy of UserGroupMembership
Apply code conventions, stable first navigation group for user, and improve spec
Merge branch 'jb/477_repair_menu'
user import: fixing date conversion issue, W52570.