NSSL-MP scheme updates

[grantfirl]

Description

This is work from @MicroTed.

This NSSL-MP update makes some improvements under the hood. No changes to the public subroutine calls.

• More accurate saturation mixing ratio calculation (iqvsopt=1)
• Changed default droplet renucleation to irenuc=5, which allows extra nucleation at high supersaturation
• A default explicit rain breakup for 3-moment rain (irainbreak=2) has been added to reduce excessive median drop diameters in rain cores, which in turn increases evaporation and cool pool temperature deficits (were too warm).
• Imposed reflectivity conservation in graupel->hail conversion (ihlcnh=3) and Bigg freezing (both 2- and 3-moment)

Answers are expected to change for suites using NSSL MP.

This PR also contains changes to the CCPP scientific documentation for the SRW v3 release. Output is here: https://dtcenter.ucar.edu/GMTB/UFS_SRW_App_v3.0.0/sci_doc/index.html

Issue(s) addressed

None

Testing

UFS-RTs on Hera

Dependencies

ufs-community/ccpp-physics#254