Doc updates from ufs v2.0.0

[llpcarson]

Description

Documentation updates from the UFS v2.0.0 release

Fixes #81

Related PRs
ufs-community/ufs-weather-model#521
NOAA-EMC/NEMS#96
NOAA-EMC/ufsatm#280
NCAR/ccpp-physics#626

How Has This Been Tested?

The ufs-weather-model regression tests pas on all Tier 1 platforms

Checklist:

Please check all whether they apply or not

• [x ] My code follows the style guidelines of this project
• [ x] I have performed a self-review of my own code
• [ x] I have commented my code, particularly in hard-to-understand areas
• [ x] I have made corresponding changes to the documentation
• [ x] My changes generate no new warnings
• [ x] Any dependent changes have been merged and published in downstream modules

[junwang-noaa]

I am not sure if I am the right person to review this PR. Rusty reviewed and approved it, I assume it is OK.

[bensonr]

@junwang-noaa - I was looking for your agreement as to whether this is the correct documentation for the develop branch to carry forward.

[junwang-noaa]

Thanks, Rusty. Yes, the UFS develop branch now points to the GFDL dev/emc branch which has all the dycore changes from ufs v2.0.0 except the decomposition reproducibility fix. I think it would be good to have the dycore document updated with v2.0.0