Add a page to explain how to use containers to prepare environments for supercomputers

[lucas-ige]

This is particularly useful for TGCC where most outgoing connections are firewalled off. With containers, environments can be created on a local machine and then uploaded to said supercomputer.

This is also good to have the exact same environment on multiple machines.

[chekki2mo]

Yes , using apptainer ( replace singularity) . I have already written something but not on github

[lucas-ige]

Sorry @chekki2mo, I had not seen your comment before -- I just committed something (PR #82) I had already written on podman on MacOS + pcocc on TGCC. Feel free to adapt.