Deprecate the old docker stack on Dockerhub

[danielhollas]

The last release of the old stack aiidalab/aiidalab-docker-stack has been more than a year ago and we don't plan new releases.

We should update the description on Dockerhub to make it clear that it is deprecated and point users to the new stack at aiidalab/full-stack. I guess this needs to be done manually by whoever has access to the aiidalab Dockerhub account. It would be nice to officially archive / deprecate the image, if this is something that Dockerhub supports.