Add access to and info for NWM 3.0 netcdf outputs

[bolotinl]

Added access to NWM 3.0 outputs in netCDF format for all available domains (Alaska, CONUS, Hawaii, PR), only through AWS. I did not re-run the scrape_gcp or scrape_nomads code, but tested that the updated scrape_aws code produces expected outputs. These new AWS options are included in an updated nwm_data.csv and nwm_data.rda file.

[mikejohnson51]

Thanks @bolotinl !