Synchronisation between AlekSIS and Django groups works incompletely

We watched problems with ...

• ... syncing owners (Person/Group side)
• ... syncing members from Person side

added part::backend prio::1 type::bug workflow::confirmed labels

created merge request !590 (merged) to address this issue

mentioned in merge request !590 (merged)

closed with merge request !590 (merged)

mentioned in commit d6a555e0