changing version of QE app breaks aiidalab-home deps in aiidalab/qe:latest

This is due on how we build the image, I think. I have to check, but I guess we always build on top of aiidalab/full-stack:latest if aiidalab/qe:latest, and I think this is wrong. Only the last image (aiidalab/qe) should be latest, and all the previous ones should have fixed version.
Requires further discussion.
To reproduce: go to manage app and downgrade to another version, then refresh the AiiDAlab home page.