Update the german readme file

[patest-dev]

Description

Updated the german readme files with missing things like installation instructions, sponsors, etc.

Contribution Checklist:

• [x] The pull request only addresses one issue or adds one feature.
• [x] The pull request does not introduce any breaking changes
• [ ] I have added screenshots or gifs to help explain the change if applicable.
• [x] I have read the contribution guidelines.
• [ ] Create an issue and link to the pull request.

[helloanoop]

Merged!

Thank you @patest-dev !