metforcing: add GEOS-IT bias reader and extend MERRA-2 lapse rate handling for sub-global domains

[Kristen-M-Whitney]

Description

Fixes #1760

This PR adds a GEOS-IT bias meteorological forcing option (GEOS-IT forcings bias-corrected using MERRA-2 climatology) to support seamless transitions from MERRA-2 to GEOS-IT forcing in LIS simulations.

It also extends the MERRA-2 lapse rate reader with:

• new configuration options for lapse rate file prefix/suffix, and
• support for using lapse rate files defined over sub-global (regional) domains that are smaller than the global MERRA-2 forcing domain.

Summary of changes:

• Add GEOS-IT bias metforcing implementation: lis/metforcing/geos_itbias/
• Update plugin registration/build configuration/documentation as needed for the new forcing option
• Update MERRA-2 lapse rate reader to support prefix/suffix configuration and sub-global lapse rate domains
• Make template precipitation handling conditional on precipitation forcing selection

Credits

• The GEOS-IT bias metforcing implementation is primarily based on the existing GEOS-IT code base and was developed by @fadjimaina with bias correction relative to MERRA-2 climatology.
• Kristen Whitney integrated the GEOS-IT bias forcing into LISF and implemented the updates to the MERRA-2 lapse rate reader, including new configuration options (prefix/suffix) and support for sub-global lapse rate domains.
• Kristen Whitney and @fadjimaina performed sanity checks and short LIS runs to verify correct forcing selection and lapse rate application.
• Feedback from @dmocko and @jvgeiger is requested.

Testcase

Sanity checks were performed to verify correct reading and application of lapse rate files. Short LIS runs were performed using both MERRA-2 and GEOS-IT bias forcings, including cases with dynamic lapse rates enabled.

[Kristen-M-Whitney]

@dmocko — draft PR is up for feedback

[emkemp]

An immediate comment: There's a lot of wasted space in geos_itbias codes due to use of old fixed-length Fortran indentation. I will switch these to free form.