Leftover (not needed?) dependency on ps_eor ?

[Alkistis]

@psahds when trying to run GPR_from_scratch_nopol.ipynb for the first time, I got an error because of the dependency of load_datacube on ps_eor. I can run this notebook by simply commenting out from ps_eor import psutil, datacube, pspec from load_datacube.py, but I assume it is still needed in other notebooks?

Perhaps good to keep this issue open and remove any dependencies for the final release :-)