Unfuck blog

What does this MR do?

The formatting in blog posts was not working due to html tags being stripped. This MR changes this by still taking care that it all stays safe and no cross-site scripting is enabled now.

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

Oh very confident - Matthias did it with me! ^^

Links to related issues

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))