Improve appearance and contenct of FAQ

[chrbertsch]

(from https://github.com/modelica/fmi-design/edit/master/Meetings/2025/2025-01-21-FMI-Steering-Committee-Meeting/README.md)

• Include links to the guides

• collect more content:

  • Does the implementation have to be C? No, only the interface ... You only have to satisfy the C API, e.g. the OSMP reference models
  • GPU calculation inside an FMU