Completely rework the German translation

[Wuzzy2]

I've completely reworked the German translation because it had many mistakes.

Things changed:

• Fixed incorrect translations of English words
• Fix capitalization of words
• Missing hyphens added
• Fixed quotation marks
• Space between word and “...” added
• Typo fixes
• Made terminology consistent

I also tested and verified the translations inside the program to find other issues (and fix them).

I know there exists an online translation platform but it didn't let me in. And editing the JSON directly was actually faster that way. It seems there has been no update to the German translation in this repository for a long time anyway, so I hope this can get merged.

[JannisX11]

Uploaded to POEditor 👍 Weird that the translation platform didn't let you contribute...