Restrict the search in a store to the store's region

Part of #1084 (closed)

What does this MR do?

The search for users inside the store management panel is restricted to people in the store's region.

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

Not perfectly sure yet, because the same search is used for other purposes as well.

Links to related issues

How to test

1. Checkout branch locally
2. Login as user2, join the region "Entenhausen" and leave the region "Göttingen"
3. Login as userbot, storemanager1, or userstorecoordination1
4. Go to a store for which you are responsible, open the store management panel (cog wheel icon)
5. Search for users to add and make sure that you can only find users from the region

For being sure that the search isn't broken in other places: check that the search still works when

• editing the members of a working group
• changing the ambassador of a region in the region admin tool (log in as userorga)

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 an entry to CHANGELOG.md
• added a short text that can be used in the release notes (only on beta)
• 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
  • 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