Add NOMADS for downloading data, update to 37 pressure levels, update solar radiation calc, hera configs

[SadeghTabas-NOAA]

Description

This PR provides updates on the gdas_utility.py script including:

• Module to get the GDAS data from NOMADS which is up to date and can be used for generating real-time GraphCast forecasts.
• It provides the functionality to run the GraphCast model on hera machine.
• Option to generate data on 37 pressure levels as well as 13 pressure levels.
• Removing PySolar package for calc of tisr as it would be calculated inside GraphCast.

Linked Issues and Pull Requests

Associated GraphCast Issue to close

• Closes https://github.com/NOAA-EMC/graphcast/issues/16
• Closes https://github.com/NOAA-EMC/graphcast/issues/17

Blocking Dependencies

Anticipated Changes

Input data

• [ ] No changes are expected to input data.
• [x] Changes are expected to input data:
  • [ ] New input data.
  • [x] Updated input data.

Needed libraries