Add section on How to deal with large artifact when using GitLab
From Mattermost:
Rok Štular: Now there's a different problem; the built book is too large for gitlab artifact collector to handle (thebe lite adds ~25MB to the book size)
Tom van Woudenberg: Would this be something which happens more often for others?
Rok Štular: On central gitlab, yes. It is something we've hit with mude, and had to change our deployment process to account for it