adding statistic page to region #582

Closes #582 (closed)

What does this MR do?

adds statistic region page with some statistics

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

actually quite - since it's mostly new things

Links to related issues

Current progress :

Menue For statistic page :

Gender statistic on two tabs (for the whole district and for the "stammbezirk")

Pickupstatistic:

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))