Feature/add run diff ranks

[twicki]

Purpose

We add a bash script to run the same resolution simulation with different number of ranks, then plot the difference between the two.

Code changes:

• plot_pcolormesh_cube: internal tool, added functionality to compare python to python output

Checklist

Before submitting this PR, please make sure:

• You have followed the coding standards guidelines established at Code Review Checklist.
• Docstrings and type hints are added to new and updated routines, as appropriate
• All relevant documentation has been updated or added (e.g. README, CONTRIBUTING docs)
• For each public change and fix in pace-util, HISTORY has been updated
• Unit tests are added or updated for non-stencil code changes