mean to inst field names, part I

[DeniseWorthen]

Description

For fields imported to FV3atm from CICE6 and CMEPS, changes the field name alias used by FV3atm by removing the 'mean' prefix. Also renames the fields being exported by FV3atm as mean_prec_rate, mean_fprec_rate and mean_prec_rate_conv to being inst fields in each case. The values of these fields used to fill the export state are unchanged.

This is the first part of a two part commit sequence to change field names from mean->inst. This first commit will not change baselines.

Issue(s) addressed

• incrementally resolves clarify "mean" and "inst" coupled fields exchanged  ufs-community/ufs-weather-model#1800

Testing

Incremental testing has been done comparing this feature branch against a baseline created using the two dependent PRs on Hera. All baselines were B4B.

Dependencies

If testing this branch requires non-default branches in other repositories, list them.
Those branches should have matching names (ideally)

• waiting on update CMEPS for refactor of esmFldsExchange_nems ufs-community/ufs-weather-model#1894
• waiting on Make exchanged field names consistent between CMEPS,MOM6,CICE6 ufs-community/ufs-weather-model#1906

[zach1221]

@DeniseWorthen testing is finished on ufs-wm PR #1925. @jkbk2004 we have the approvals needed, can you please go ahead to merge this PR?