Rename "Literature" to resources and add addtional resources

[chrbertsch]

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

"Literature" shall be a subsections

Collection for additional content:

• Implementers' guide
• videos (e.g. from ASAM conference)
• FMI Beginners' tutorial + Video
• Starting point to create FMUs from C-Code ...
• (please add to this list)