add/remove Admin/ambassador over memberlist

What does this MR do?

• Allows ambassadors to remove members from the memberlist.
• Allow admins to remove / add admins over memberlist TODO: manage ambassadors over memberlist

How confident are you it won't break things if deployed?

WIP

Links to related issues

How to test

1. Checkout branch locally
2. Login as ambassador
3. go to memberlist
4. Remove foodsaver
5. Login as orgauser
6. go to memberliste of district
7. remove a bot as ambassador
8. reload page to see that it worked
9. set a bot as ambassador
10. reload page to see that it worked

Screenshots (if applicable)

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• set a "for:" label to indicate who will be affected by this change
• used "state:" labels to track this MR's state until it was beta tested
• added to the next milestone (see https://gitlab.com/foodsharing-dev/foodsharing/-/milestones, unless it has a "for:Dev" label)
• added an entry to CHANGELOG.md
• added a short text that can be used in the release notes
• Once your MR has been merged, you are responsible to create a testing issue in the Beta Testing forum: https://foodsharing.de/?page=bezirk&bid=734&sub=forum. Please change the MRs label to "state:Beta testing".
  • Consider writing a detailed description in German.
  • Describe in a few sentences, what should be tested from a user perspective.
  • Also mention different settings (e.g. different browsers, roles, ...) how this change can be tested.
  • Be aware, that also non technical people should understand.

Release notes text in German

Über die Mitgliederliste eines Bezirkes ist es nun möglich für Orgaberechtigte, Botschafter einzusetzen und auszutragen. Über die Mitgliederliste in AG's können Admins nun Mitglieder als Admins eintragen und austragen.