Add 3.0 outputs

[sepehrkrz]

NWM Version 3.0 includes outputs for Alaska and coastal which should be included in nwmurl library.
Those files are here:
https://noaa-nwm-retrospective-3-0-pds.s3.amazonaws.com/index.html

[jameshalgren]

We could include the somewhat trivial url endpoints for the .zarr outputs archived at that site (e.g., https://noaa-nwm-retrospective-3-0-pds.s3.amazonaws.com/CONUS/zarr/forcing/precip.zarr/)

While not as beneficial as the larger sets of netcdf output files, due to the much more efficient access pattern of these larger zarr files, it could be helpful to make the nwmurl library complete from the user perspective.

The usage pattern for the monolithic .zarr files is templated on dataaccess.ciroh.org