add a section on privacy and on reasonable uses of the cluster

[gyom]

There have been discussions with the head of cybersecurity, and it has come to light that there are no indications in our documentation about the fact that it is not okay to use the Mila cluster for mining cryptocurrency or for random startups by students.

This also bring about the question of using the Mila cluster for coursework, and I don't even think that there is a definitive answer there. Technically, this is not allowed for non-research purposes, but I would personally argue that making a light use of the Mila cluster in the context of PhD courses will lead students to make better use of the Mila cluster afterwards in their "real" research. My point is that the answer to that question is not found in the documentation.

Moreover, another hot topic is about privacy. It's "obvious" that students should not be storing their personal collection of Disney movies DVD rips on the Mila cluster, but is it spelled out anywhere? What about illegal Atari ROMs that are in every RL test suite? Are the Mila admins allowed to scan the users' folders with a script to detect certain kinds of misuses? What are the reasonable expectations from the part of students?

This issue isn't going to be solved with a PR written by a single person in 10 minutes, but it needs to be tracked.

[lebrice]

Could perhaps tackle this alongside #190

[lebrice]

Also maybe #45 ?