Multiple coupling options for the same application

[danrosen25]

Applications often need more than one coupling configuration setting. For example NEMS at least uses 'nems_orig', 'nems_orig_data', 'nems_orig_active', 'nems_frac'. HAFS will similarly need multiple settings during the research and development phase. I believe the 'coupling_mode' configuration needs to be broken up. If not then I can add specialized configuration options directly into the hafs_mod and pass them in through the gcomp attributes.