Sixth reconciliation PR from production/RRFS.v1

[grantfirl]

Description

This PR contains changes from 2 PRs that went into production/RRFS.v1:

• [production/RRFS.v1] Parallel IO enhancements from GDIT #818 from @MatthewPyle-NOAA

Provides the changes needed to take advantage of FMS parallel IO changes. Changes courtesy of Dan Kokron of GDIT. Will be paired with changes in atmos_cubed_sphere

• [production/RRFS.v1] Add clear-sky shortwave downward at surface flux to available diagnostics. #825 from @dustinswales

This PR adds a new diagnostic, instantaneous downward shortwave flux at the surface assuming clear-sky conditions.

Issue(s) addressed

None

Testing

Tested on Hera using full rt.conf. See logs in UWM PR: =

Dependencies

ufs-community/ccpp-physics#235
NOAA-GFDL/GFDL_atmos_cubed_sphere#365

Requirements before merging

• All new code in this PR is tested by at least one unit test
• All new code in this PR includes Doxygen documentation
• All new code in this PR does not add new compilation warnings (check CI output)