Improve subprocess CRDS calls for easier debugging

[mcara]

Recently there were a couple of helpdesk issues (INC0155647 and INC0156501) when users reported errors with running CRDS commands using subprocess. One difficulty in understanding the cause of the errors was that suprocess in some notebooks is not set up to output errors. This PR modifies calls to subprocess.check_output()so that messages from CRDS can be read in the notebook.

[bhilbert4]

I don't know if it is relevant or useful here or not, but here's an example of using the CRDS API: https://github.com/spacetelescope/mirage/blob/master/mirage/reference_files/crds_tools.py#L141

[mcara]

I would say that I just want to improve one aspect of existing notebooks to address a specific issue. If there is desire to re-design the notebooks, that could be done too as a separate PR.