Add / link content by Johannes Bottcher

[koppor]

@johannesbottcher wrote a good text about biblatex. It should be made more public. Maybe, integrate in the manual or in the upcoming docs.jabref.org (https://github.com/JabRef/docs.jabref.org)

https://github.com/johannesbottcher/HinweiseLitverzeichnisse/blob/master/Hinweise.md