WRF-Chem pre-release

Pre-release version of WRF-DART with WRF-Chem capabilities

Documentation available at https://docs.dart.ucar.edu/en/wrf-unified/.

wrf_unified model_mod page

We recommend you checkout the wrf-unified branch to get the latest developments on this code:

git checkout wrf-unified
git pull

Summary of changes:

• Unifies wrf and wrf_chem capabilities into a single model_mod
• removes wrf_static_data_for_data, uses state_stucture_mod
• Removed wrf%dom%type so any netcdf variables can be added to the state via namelsit
• 2M variables forced to 2M QTYs
• QTY_TEMPERATURE forced to QTY_POTENTIAL_TEMPERATURE
• No vortex forward operator

Pull request #741

Please reach out to dart@ucar.edu if you are interested in using WRF-Chem.