Updated Python plotting script for UFS SRW app (#250)

* Updated Python plotting script

* Update python plotting script to use env.yaml

plot_allvars.py now includes the following changes:

- env.yaml is read in and variables assigned in the env.yaml
(EXPT_BASEDIR,EXPT_SUBDIR, and CARTOPY_DIR) are used. This file
still has to modified by the user before plotting.

- Variable "domains" in plot_allvars.py can now be set to
"regional". This will read in domain variables from grib2 input to
setup the map extent. This assumes a lambert conformal output.
CONUS option is still available and unchanged.

- Cartopy cannot plot geopolitical boundaries at this time due to
restrictions on NOAA machines. The variable CARTOPY_DIR is created
in env.yaml to point to a base directory where the user can upload
the necessary shapefiles if needed.

- Input grib2 file name was changed to reflect output names coming
from UPP.

* Change to include new file naming convention and model name

Change made to update file naming conventions in the following:
- Remove "compare" from .png output files
- Modify the title from FV3SAR to FV3-LAM
- Change the default path to: /path/to/exp/dir/'+str(ymdh)+'/postprd/RRFS.t'+cyc+'z.bgdawp'+fhour+'.tm'+cyc

* Add cartopy shapefiles and directory paths as command line arguments

* Change name for grib2 file and remove compare string from plot names

* Change rrfs string to lowercase for grib2 file

Co-authored-by: David Wright <david.m.wright@noaa.gov>

ush/Python/env.yaml

@@ -0,0 +1,3 @@
+# This is a yaml file to define the Python virtual environment
+# I do not yet know how to set this up so if anyone wants to do it go ahead!
+#