Third followup from search improvements

What does this MR do?

Fixes issues raised in beta testing:

• For Orga users, searching is too slow. Therefor they get the option not to search globally.
• Fetch the search index not with every page load but at most once every 5 minutes
• Fix minor display inconsistancy
• allow finding the own profile in the search
• sort chat search results properly
• Closes #1785 (closed)

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

quite confident

Links to related issues

https://beta.foodsharing.de/region?bid=734&sub=forum&tid=230569

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
• 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 in the release notes to /release-notes/YYYY-MM.md
• Once your MR has been merged, you are responsible to create a testing issue in the Beta Testing forum: https://foodsharing.de/region?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.