run jupyter-lab through singularity or docker

[jfleroux]

We use Singularity containers with conda env inside to launch jupyter-lab on HPC to get rid of system issues.
the line written in the script should be configurable :
source activate conda_env && jupyter lab --no-browser --ip=$(hostname -f)
to something like that
singularity exec conda_env.sif jupyter-lab

Or use a template file to be more generic ?