Consolidate post scripts to eliminate coupled mode of link script (NO…

…AA-EMC#766)

The two scripts that had modified versions for the coupled model have been joined with changes to the original scripts, eliminating the need for a special coupled mode for the link script. As part of this, those two scripts are no longer copied from UPP and are now part of the global-workflow repository.

Fixes: NOAA-EMC#679
Fixes: NOAA-EMC#746
Refs: NOAA-EMC#270

.gitignore

@@ -123,7 +123,6 @@ scripts/exgdas_enkf_post.sh
 scripts/exgdas_enkf_select_obs.sh
 scripts/exgdas_enkf_sfc.sh
 scripts/exgdas_enkf_update.sh
-scripts/exgfs_atmos_nceppost.sh
 scripts/exgfs_atmos_vminmon.sh
 scripts/exgfs_atmos_wafs_blending.sh
 scripts/exgfs_atmos_wafs_blending_0p25.sh
@@ -142,7 +141,6 @@ ush/chgres_cube.sh
 ush/emcsfc_ice_blend.sh
 ush/emcsfc_snow.sh
 ush/fix_precip.sh
-ush/fv3gfs_downstream_nems.sh
 ush/fv3gfs_driver_grid.sh
 ush/fv3gfs_dwn_nems.sh
 ush/fv3gfs_filter_topo.sh