Internationalization and Localization - Part 1

[yulieth9109]

This pull is to Include the internationalization package and the Generated arb files with the keys of the text translated.

[7h30n3]

All keys should be English, not a mix between English and German like about_quellcode.

[7h30n3]

Numbering keys should be avoided as it doesn't give the appropriate context, where and how the key is used.