Structured data for "General Information" / FAQ

Replaces https://github.com/fipguide/fipguide.github.io/issues/122

For now, we have no break-through-solution for adding structured information to general information.
https://developers.google.com/search/docs/appearance/structured-data/faqpage?hl=de

Formerly branch / PR: https://github.com/fipguide/fipguide.github.io/pull/222