translated to german

This commit is a combination of squashed commits from pull request by
@basilstotz. Closes #37

Commits:

added german translation

Update feedback.json

Update logout.json

Update menuitem.json

translated to german

Update search.json

translated to german

Update feedback.json

Update config.json

added german translation

added german translation

added german translation

added german translation

added german translation

added german translation

added german translation

added missing colons