WIP: Jb 339 Partnerseite CSS Update

Closes issues0#339

What does this MR do?

Adjust CSS for partnerpage change height to min-height and max-height for the partner contaier to be more flexible

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

quite sure

Links to related issues

https://gitlab.com/foodsharing-dev/issues0/issues/339

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))