Added German Translation and updated Descriptions

Whoopeee, another pull request! Awesome, right? I'm slowly getting the hang of it. :smile_cat:
This particular pull request is accomplishing the following:

* Added German Translation for our [Android IMSI-Catcher Detector](https://github.com/SecUpwN/Android-IMSI-Catcher-Detector)
* Moved "Thank you" out of `Security Notes` and into Project Description

I'd be happy if @nylira or @Zegnat could merge this soon to enable a quick error-check. Thanks.