Use released batchspawner

[aktech]

Context

Update jupyterhub environment to use batchspawner from pypi/conda-forge

https://github.com/nebari-dev/nebari-slurm/blob/363888306663018620a803d9e906482eef9b7e9b/roles/jupyterhub/templates/environments/jupyterhub.yaml#L18

Value and/or benefit

Now that batchspawner is released:

• https://pypi.org/project/batchspawner/
• https://anaconda.org/conda-forge/batchspawner

It would be great to remove pulling batchspawner directory from github and pull it from pypi or conda-forge

Anything else?

No response

[aktech]

This is done: https://github.com/nebari-dev/nebari-slurm/blob/5f39db41a330f1e2963d48e5d5f0851dbbfd7271/roles/jupyterhub/templates/environments/jupyterhub.yaml#L12