Plotting scripts should be part of the workflow

[danielabdi-noaa]

Description

Currently plotting scripts under ush/Python are standalone scripts run optionally by the user. I believe they should be part
of the workflow.

Solution

• Create a new rocoto task plot_allvars to handle this as part of the workflow. This will avoid the need for the job submission scripts sq_job.sh and pbs_job.sh etc
• plot_allvars_diff.py plots the difference between two experiments so the experiment would need to know which other experiment it needs to compare to.
• Remove the ush/Python folder once the above solution is implemented

Requirements**

pygraf environement is needed. Cartopy shapefiles are needed but seem to be available on Tier-1 platforms according to the docs: https://srw-ug.readthedocs.io/en/release-public-v2.1.0/Graphics.html

Update:: pygraf environment seem to be part of regional_workflow environment now with the new EPIC modulefiles so no new packages are necessary.

Acceptance Criteria (Definition of Done)

• Produce graphics as part of the workflow
• Both raw and diff graphics
• Can be optinally turned off