One of the developers in our team accidentally deleted our collaborative projects and got stern warning from our project lead.Luckily we were able to restore the data from one of the gitlab backups(oh the irony).Since then we use gvfs-trash command every time we have to delete anything from ubuntu server since it moves files to trash.You can write bash script or cron job to periodically empty the trash if disk space is an issue.
Moral of the story learn from your mistakes and use safe delete commands instead of misusing rm -rf
But we have to appreciate the efforts of gitlab to provide such a nice platform for developers and remember that at the end of the day it is still run by developers who might make mistakes just like all of us.