Clean up how fixed files are staged - remove the ".agent" concept.

[MatthewPyle-NOAA]

The linking from the fix directory in the built workflow to ../../.agent/, which then points at a central location on WCOSS disk may make sense for development work to avoid multiple copies of the same large static files, but we need a cleaner solution for code hand off.

Ideally would have some form of an "install_rrfs_fix.sh" script that could have link and copy options to populate the fix/ space in the workflow (could live alongside the sorc/app_build.sh script).