added German (de) localization messages

[floookay]

PR Checklist

Please check all that apply to this PR using "x":

• I have checked that this PR is not a duplicate of an existing PR (open, closed or merged)
• I have checked that this PR does not introduce a breaking change
• This PR introduces breaking changes and I have provided a detailed explanation below

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting)
• Refactoring (no functional changes)
• Documentation changes
• Other - Please describe: Added German localization messages

Fixes

Issue Number: #76

What is the current behavior?

What is the new behavior?

Other information

[btzr-io]

@floookay Nice, thanks ✌️