update to take the appropriate spack env environmental variables without having to list explicitly all the tools

parametrized even more the path that the JupyterLab kernel will be
created

Move the NFS folder that the configuration of the JupyterLab spackified kernels lie outside a particular environment's location

Added create_JupyterLab_kernel.sh script that creates a spackified JupyterLab kernel conf and places it to NFS where it can be loaded by all users based on the instructions contributed by Eric Mueller