Add heat content associated with Forr_rofl_glc and Forr_rofi_glc

Following the implementation of glc->ocn coupling via going through mosart (https://github.com/ESCOMP/CMEPS/pull/463), the heat content (or enthalpy) associated with these fields must be computed and provided to OCN. [here](https://github.com/ESCOMP/CMEPS/pull/278/) is a PR that can be used as an example of adding enthalpy fields in CMEPS.

For now, we can compute `Foxx_rofl_glc` following what's done for `Foxx_hrofl`. Similarly for `Foxx_rofi_glc` and `Foxx_hrofi`.

These changes are needed for https://github.com/NCAR/MOM6/pull/288