Generic script to create grib products using wgrib2

[aerorahul]

Create a new generic product generation job that uses a set of python/yaml-based scripts to create regridded GriB products to replace the existing portion of the post script that does that. The post portion of the existing scripts will be handled separately in #1429

[HenryRWinterbottom]

Here is an example application from UFS-RNR:

https://github.com/NOAA-PSL/UFS-RNR/blob/ce7122cd4a8e80b0fbeed4fc27def8e6509b4f26/ush/tools/grib_interface.py#L568

[aerorahul]

The shell scripts have been refactored to make this cleaner compared to v16. We can close this issue as not planned.