Add updated omega calculation pass to ufs-wm

[dpsarmie]

Description

A new feature was added in FV3 to calculate omega for non-hydrostatic runs (#2327). Changes were made in global-workflow to implement these changes into their runs (NOAA-EMC/global-workflow#2751) and this PR will add the new omega calculation for all regression tests that are non-hydrostatic.

Solution

Change default_vars.sh to switch on the omega calculation for non-hydrostatic runs, change the diag_tables to allow for 'omga' output, and add a new field in the global namelist.

Related to

Related to #2327 for the initial implementation of the new omega calculation and NOAA-EMC/global-workflow#2751 for the relevant global workflow PR.