New sea ice fields (pond area fraction, snow melt rate, and snow-ice formation rate) and updates to existing analyses

[eclare108213]

Add new fields: pond area fraction, snow melt rate, snow-ice formation rate.
Add additional seasons and/or change them for all fields except those that already have observational data.
Adjust color bars, especially for differences.
Change tag from 'snow' to 'snow-on-sea-ice'.
Clean up some comments.

Testing:
https://web.lcrc.anl.gov/public/e3sm/diagnostic_output/ac.eclare/E3SMv3/MPAS_analysis/1985-2014/snow_control-off/sea_ice/index.html

Documentation: https://web.lcrc.anl.gov/public/e3sm/diagnostic_output/ac.eclare/html/users_guide/tasks/climatologyMapSeaIcePondAreaSH.html

Checklist

• User's Guide has been updated
• Developer's Guide has been updated
• API documentation in the Developer's Guide (api.rst) has any new or modified class, method and/or functions listed
• Documentation has been built locally and changes look as expected
• Testing comment in the PR documents testing used to verify the changes

[eclare108213]

I will clean up default.cfg, and I still need to pull the whole thing to my laptop to be able to test the documentation.

[eclare108213]

Ready for review.

[xylar]

Thanks @eclare108213! I'll take a careful look tomorrow.

[xylar]

Sorry, my testing is being delayed by problems with Chrysalis. I don't have access to Compy right now and the queue times on Perlmutter are too slow to be useful, so I'll wait and see if I can test over the weekend.

[xylar]

@eclare108213, sorry for the delay in reviewing this. I really appreciate this excellent work. It passes my test suite and the code and documentation looks great, as do the new plots.

It is so exciting to see the sea-ice analysis getting fleshed out. I think we will learn a lot from this. Thank you!