Jupyter Jobscript issues on Nesh

@patricia-handmann reported problems with job-scripts/nesh-linux-cluster-jupyterlab.sh.

Let's work towards a solution here, because this is the place where all of the people who can be of help are available. (Personally, I didn't do any own work on Nesh for > 6 months and hence might not be able to help at all.)

@patricia-handmann: Can you add some details here?

• What's your conda installation, and how do you activate it if you use it directly on the frontend?
• What jobscript are you using and how do you submit it?
• What's in the job-output?
• What does qstat say while the problematic job is running?