make more comments to walls accessible. #630

Closes #630 (closed)

What does this MR do?

Walls such as for baskets or events have been limited to 30 comments. I have set it to 60 and made the method variable for future uses.

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

Very

Checklist

• added a test, or explain why one is not needed/possible... (should be covered by existing tests and my visual review.
• no unrelated changes (suuuper small refactor regarding code style in this function)
• 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))