Overhaul README

[realguse]

Description

This PR will hopefully do a good job of cleaning up the enormous and kind of confusing README. I have plans to short it down, make it look prettier and add a section that links to available languages. This will most likely take some time to complete.

Requirements / Checklist

• Read the Contributing Guidelines
• I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan.

Inspiration

Inspiration for the language section

[Finii]

Thanks for starting work on the readme. That is indeed a mess and needs cleanup, but doing it carefully and without breaking expectations by long time "old" users is not so easy. I also believe it should be much much smaller and rather link to subtopics - but then searchability can be a problem. Anyhow, you are right, this needs to be worked on.
I started it ... twice iirc, but the final result was also not too nice or it was just too different 😬 Some information in there is too prominent imho and the impression it transports can be wrong. Yes, difficult.

This is still a draft, but let me quickly add two thoughts.

1. Why are the links replaced by raw url strings. This does not improve the readability but degrades it. We had all links in the bottom of the file before. And then, while the symbolic links are replaced by concrete urls, the link definition is not removed? 🤔
2. I would not promote the translates readmes at all. They are a maintenance nightmare, and I would rather remove them because they are so utterly outdated.