Add and adjust various German translations in portal.json

[lsinger]

• There's a clear use-case for this code change, explained below
• Commit message has a short title & references relevant issues
• The build will pass (run yarn test:all and yarn lint)

This PR adds and adjusts various German translations in portal.json. I'm a native speaker and have made adjustments to the best of my knowledge. As in #21163, the gender variations are a bit opinionated and I'm happy to discuss.

[cathysarisky]

from thewolfofallstreetz (Ghost forum): the (green) translations look good to me.

Only minor comment on 2: “(save {{highestYearlyDiscount}}%)”: “(jetzt {{highestYearlyDiscount}}% sparen)”

This string will show the highest discount of all the offered packages. So the discount will be “save up to” x%, but it could also be less.

To correctly express this in German you could say the following: (save up to {{highestYearlyDiscount}}%)": “(jetzt bis zu {{highestYearlyDiscount}}% sparen)”

My response: The string actually shows the price difference between monthly and yearly. So if you pick yearly, you’ll actually get the discount compared to monthly. I think "up to" is probably not needed here.

@lsinger, thanks for all your work to polish these! :)