transfer nf-core/rnaseq tutorial on nf-core/rnaseq repo

[lescai]

This issue is to track the work needed to add the tutorial on nf-core/rnaseq under /usage on nf-core/rnaseq repo during the hackathon October 2024

For documentation:
the material in .md files should be added under /docs by creating a /usage folder in
https://github.com/nf-core/rnaseq/tree/dev/docs
each .md page under /usage will be linked on the left hand side on the rendered nf-core website

see here:
https://github.com/nf-core/crisprseq/tree/master/docs/usage
rendered here:
https://nf-co.re/crisprseq/2.2.1/docs/usage/

[mashehu]

I think this is the wrong repo for this issue 🙂