Update Makefiles to default to FMS2; MOM6 update

The Makefiles for each model have been updated to include a variable to the FMS source directory (FMS_CODEBASE) which is now passed to the FMS Makefile.

FMS_CODEBASE defaults to the FMS2 source, in order to align with autoconf changes in MOM6 which now default to FMS2 API. The AM2-based models default to FMS1, with separate FMS1-based build directories for FMS, icebergs, and ice_param.

The FMS1 source and FMS symbolic link have been preserved, so no exisiting mkmf-based builds should be affected by this change.

The MOM6 submodule has also been updated, which includes the commit which updates the default autoconf FMS API (f9da67331).

Updated commits:

NOAA-GFDL/MOM6@714d2da17 Minor refactoring in set_viscous_BBL
NOAA-GFDL/MOM6@e1ea75847 Add the debugging routine test_L_open_concave
NOAA-GFDL/MOM6@da02ffc60 +Add find_L_open_concave_iterative
NOAA-GFDL/MOM6@2ae638504 Refactor set_viscous_BBL channel drag calculations
NOAA-GFDL/MOM6@f9da67331 Create BUILD and WORK directory macros
NOAA-GFDL/MOM6@fd5696ba0 Pinning package requirements for readthedocs
NOAA-GFDL/MOM6@d0e9c25a0 *Corrected CFC diagnostics and non-Bous CFC fluxes
NOAA-GFDL/MOM6@8f7df084d (*)non-Boussinesq Z unit update_OBC_segment_data
NOAA-GFDL/MOM6@86c5ed989 (*)Fix bug in h_neglect used to remap diags to rho
NOAA-GFDL/MOM6@f2e7abff8 MLE: Use default answer date outside of block (#570)
NOAA-GFDL/MOM6@e69d77107 Merge branch 'main' into dev/gfdl
NOAA-GFDL/MOM6@2ab885edd Merge pull request #1616 from NOAA-GFDL/dev-gfdl-main-candidate-2023-11-13
NOAA-GFDL/MOM6@6d7c00a83 Restore bit repro using FMA in selected runs
NOAA-GFDL/MOM6@f92e4ac31 Update MOM_mixed_layer_restrat.F90 (#568)
NOAA-GFDL/MOM6@3f7465a57 +tracer_Z_init can rescale tracers
NOAA-GFDL/MOM6@f14a68107 (*)Use thickness_to_dz with BRYAN_LEWIS_DIFFUSIVITY
NOAA-GFDL/MOM6@0fb905fdc +(*)non-Boussinesq ALE_sponges work in Z units
NOAA-GFDL/MOM6@c37a2f0d0 Document core and linear EOS variable units
NOAA-GFDL/MOM6@de7e5b79f Document MOM_regridding and coord variable units
NOAA-GFDL/MOM6@4757bcb52 Remove some unused calculations if non-Boussinesq
NOAA-GFDL/MOM6@9282cd100 +(*)Bodner param with cuberoot and non-Boussinesq
NOAA-GFDL/MOM6@ea12532d8 Fix issue with restart filenames when using ensembles.
NOAA-GFDL/MOM6@9a6ddee47 *+non-Boussinesq revisions to MOM_generic_tracer
NOAA-GFDL/MOM6@e7a7a82ab (*)MOM_temp_salt_init_from_Z Z-unit tracer remap
NOAA-GFDL/MOM6@915cfe225 +ALE_remap_scalar with arbitrary thickness units
NOAA-GFDL/MOM6@07bace68c *Fix two bugs in convert_temp_salt_for_TEOS10
NOAA-GFDL/MOM6@671c85d32 (*)Use cuberoot in ePBL_column
NOAA-GFDL/MOM6@736ef16a4 Cuberoot: Break **3 into explicit integer cubes
NOAA-GFDL/MOM6@5edba9b4d Cuberoot: Refactor (re|de)scale functions
NOAA-GFDL/MOM6@60cb551a3 Intrinsics: Faster cuberoot scaling functions
NOAA-GFDL/MOM6@76f066814 (*)Avoid using RHO_0 in non-Boussinesq averaging
NOAA-GFDL/MOM6@541c2f479 (*)Oil_tracer_column_physics unit conversion fix
NOAA-GFDL/MOM6@0de5c1493 Merge pull request #1618 from jiandewang/DEV-EMC-candidate-20230122
NOAA-GFDL/MOM6@5ca70bac6 Open parameter block before querying BODNER23
NOAA-GFDL/MOM6@f1e0f01a8 Params: Add do_not_log to param block open/close
NOAA-GFDL/MOM6@435ccaae4 Data table documentation (#551)
NOAA-GFDL/MOM6@17f1c40df Cuberoot: Apply first iteration explicitly (#11)
NOAA-GFDL/MOM6@4813b17c2 *Use Halley method iterations in cuberoot function
NOAA-GFDL/MOM6@c8a7325c0 Merge pull request #126 from DeniseWorthen/feature/restartfh
NOAA-GFDL/MOM6@d7d126a7f Update Gaea F5 datasets path
NOAA-GFDL/MOM6@d9c7bd950 Merge branch 'NOAA-EMC:dev/emc' into feature/restartfh
NOAA-GFDL/MOM6@a728ceaa5 allow restarts to be set on non-interval hours
NOAA-GFDL/MOM6@60c397b91 Merge pull request #124 from jiandewang/feature/update-to-main-20231218
NOAA-GFDL/MOM6@a03bb957c +Add cuberoot function
NOAA-GFDL/MOM6@db62734a9 Merge remote-tracking branch 'MAIN/main' into feature/update-to-main-20231218
NOAA-GFDL/MOM6@40134ed86 change target to pointer and check for association
NOAA-GFDL/MOM6@7ef6a5725 Fix the saltFluxAdded diagnoistic, broken in #401
NOAA-GFDL/MOM6@f4c95ec4b Revert post_data fix to CFC concentration
NOAA-GFDL/MOM6@a36cb73d6 Merge pull request #122 from jiandewang/feature/update-NCAR-GMAO-20231031
NOAA-GFDL/MOM6@80a93f633 Merge remote-tracking branch 'MAIN/main' into feature/update-NCAR-GMAO-20231031
NOAA-GFDL/MOM6@e2c322eed Merge remote-tracking branch 'MAIN/main' into feature/update-NCAR-GMAO-20231031
NOAA-GFDL/MOM6@02d4dc455 Merge pull request #120 from DeniseWorthen/feature/fldnames
NOAA-GFDL/MOM6@abb0ad24f switch to cesm-style field names

NOAA-GFDL / MOM6-examples

Update Makefiles to default to FMS2; MOM6 update #441