Ai string translation

[mschuettlerTNG]

The following things have been changed:

• all displayed text has been made translatable
• the en-US.json has been made more cohesive
• the de.json has been proof read
• en-US.json and de.json have been used together with the old json files of the other languages to generate the updated json files (we used predominantly Llama 3.3 70B and Claude 3.5 Sonnet)
• format and linter changes

What is still missing:

• the translation of the "Learn more" page (waiting for the new page design)