Handle fix file staging and versioning.

[christinaholtNOAA]

The RRFS_dev1 solution to stage the appropriate version of fix files relies on commit hooks and staging files on disk and/or HPSS. We need a solution for how to ensure fix files are appropriately staged that is machine independent and a standard practice.

The preferred method is to store them in a globally accessible, centralized location. Versioning should follow a standard versioning control method that can handle large files -- svn or git with LFS. The files should be staged on supported platforms from the central location, for ease of use. SRW should know where to get them and where to put them for an experiment.

The fix files required for RRFS involve the pre-generated grid files for supported grids, the GSI fix files, and the global FV3 fix files.

[christinaholtNOAA]

Eddy has been handling this -- there's a document for status and what's moved. Should be good for Jet/Hera. Still need to add a PR for the Bay Area grid.

[christinaholtNOAA]

This is ongoing work for the duration RRFS merge project. There's nothing to be addressed currently.

[gspetro-NOAA]

@christinaholtNOAA Is this something your team is working on, or is this something EPIC should be handling?