Add german translation

[DaVukovic]

As I received help here I thought it might be a good idea to give something back.

Not a experienced developer at all, so please bear with me if you might find any issues. I'm absolutely not sure if the edits I've done for the CONTRIBUTING.md file are correct.

Please feel free to give any kind of feedback and I happily amend some edits

I tested this with Ubuntu 16.04 and 18.04 and AFAICT, I can't find anything missing.

[DaVukovic]

I'm not 100% sure, but I would say, the error is not related to my PR. Maybe @lupoDharkael could take a look.

[holazt]

@DaVukovic I‘m sure that's a problem of travisci.

[DaVukovic]

Thanks for answering. Thought so.

[AlfredoRamos]

It seems to be a timeout. You can close and re-open the this pull request to trigger the tests again.

[lupoDharkael]

I'll restart the build

[DaVukovic]

rebased and merge conflicts solved

[lupoDharkael]

The CI seems to be failing due to RPM errors. @ZetaoYang any idea?

[holazt]

@lupoDharkael @DaVukovic

Travisci error:

lrelease error: Cannot open translations/Internationalization_de.DE.ts: No such file or directory

Appveyor error:

lrelease error: Cannot open translations/Internationalization_de.DE.ts: The system cannot find the file specified.

Name of Internationalization_de.DE.ts is not standard. (P.S. Why _de.DE. is? Please try _de_DE again.)

[DaVukovic]

Yeah, seen that already. Just haven't found the time. Most likely an error on my side.

I'll let you know if I can solve it

Thanks for the heads up ;)

[DaVukovic]

Let's hope it was a typo only ;)

[holazt]

@DaVukovic @lupoDharkael It could be merged now.

[lupoDharkael]

Thanks!