Some narrative discrepancies when using CSD3 vs AWS

[tavareshugo]

In the SLURM section, we still have examples for our AWS setup, rather than the new CSD3 setup we use.

It might be good to change this back.

Maybe to avoid loosing information (in case we run it on AWS again) I can find a way to do some conditional chunks of materials, or use tabset to switch between them.

[RaqManzano]

See exercise 1 in the intro: https://cambiotraining.github.io/hpc-intro/materials/02-ssh.html#exercise-ssh