field names in nuopc/cmeps cap should be consistent with CMEPS

[DeniseWorthen]

Currently there is a mix of field names being used in the CICE6 cap for CMEPS, meaning some field names are specified CESM-style (F = flux, S = state) and some using descriptions (mean_xxx_flux). This was the result of unifying the CICE6 cap between CESM and UFS at the same time that UFS was transitioning from the NEMS mediator to the CMEPS mediator. The CMEPS mediator in both CESM and UFS uses only CESM-style field names to define the exchanged fields.

Although not required for functionality (because of aliasing field names), it is clearer from a user perspective and for developing UFS documentation if the naming convention is consistent between the mediator and the caps.