ResOps requirements, both runtime and user

for the gitlab exercises, users are required to edit files. This means that they will need an editor (vi, nano, whatever) installed in the exercise VMs, and also that we need to state that they need to know how to use one of these editors in the pre-requisites for the course.

David, can you confirm that there are suitable editors there, then assign this to CD to update the pre-requisites in eventbrite so we tell them about it in future?