Remove the dust emissions namelist items from CTSM and use the namelist in the drv_flds_in for CMEPS.

This updates CTSM to use the namelist control in CMEPS (in ESCOMP/CMEPS#429). So the CMEPS external needs to be updated, and the
namelist control in CTSM changed to use CMEPS rather than the internal CTSM control settings and the CTSM ones removed.

The new XML variable:

   LND_SETS_DUST_EMIS_DRV_FLDS

controls whether dust emission settings are set by CTSM or by CAM. Only one or the other can set them, and it's required so when CAM
and CTSM are running together they need to know which one will select.

This required some changes for LILAC. The drv_flds_in namelist file is now required for LILAC, and read for dust emissions
(and dust emissions only) at the LILAC lnd_comp_esmf.F90 level.

Add a unit test for the CMEPS code to make sure it's working correctly. This validates the code both for CAM and CTSM.

Fix the cidinahoBR test in the build-namelist unit tester.