Added version tag to datasciecne-notebook-version

The latest version of datascience-notebook seem to be incompatible with the jupyterhub version, we are using right now. This fixes the version via image tag in the tools.json.

This is on the old version that is still used by nomad. It should be just a temp fixed and does not need to be merged. See also !130 (closed) for the actual fix.

closed