Bug#978557: lutris: Add German translation

[Stephan Lachnit]

Hi Sven,

> there is a German translation patch available in my own Github repostitory


Cool, thanks for your contribution! I gave it a quick review, loogs good to me. Can you open a PR upstream? I want to avoid downstream patches.

> To use the newer development version build of lutris I had to install the package python3-lxml

Thanks for catching that! Opened a PR upstream: https://github.com/lutris/lutris/pull/3355

Grüße,
Stephan