WIP: Move team status out of team list in a extra menu

What does this MR do?

As the teamlist is collapsed in stores after !983 (merged) got merged, the menu of switching the store join status isn't as present anymore on mobile. I always thought it is wrong to place this join status under the teamlist as it should be placed into store settings.

I don't want to move it there right now as it would cause problems to !905 (closed) where some decisions are open. Also as I understand settings don't allow the requiered attribute, which is checked here by javascript.

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

Works fine locally

Links to related issues

• Reaction to !983 (merged)
• Similar change !905 (closed)

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))