Addition to page: Trainer

I would like to suggest you to add the following resources to the Trainer page at `/trainer`. You talk about "Make sure that the training material is as FAIR and open as possible.", but you missed to indicate the references to how:
- https://elixir-europe-training.github.io/ELIXIR-TrP-FAIR-training-handbook/
- https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1007854

Thank you :).
best,
Patricia