Add capability to use other ATM ICs than GEFS Noah LM for coupled experiments

[ulmononian]

Currently, GEFS-NoahMP-aerosols-p8a are the default atmospheric ICs for coupled runs and the workflow automatically stages these files when running a coupled experiment (global-workflow/parm/config/config.couple_ic). However, the dates of these ICs are limited (Orion: /work/noaa/global/wkolczyn/noscrub/global-workflow/IC/GEFS-NoahMP-aerosols-p8a/ ; Hera: /scratch2/NCEPDEV/climate/climpara/S2S/IC), and do not cover all available ICs for ocean, sea ice, and waves. This precludes flexibility for users to run cases at preferred start dates/times. Would it be reasonable to allow other ATM ICs to be utilized (e.g., GFS ICs, as used in uncoupled runs) to enable coupled runs to begin from a broader date range? I suggest adding this capability, either through a conditional statement in the config.couple_ic file or in the ./setup_workflow_fcstonly.py script.