Modified ocean/mesh/remap_topography to allow smoothing

[bmooremaley]

The ocean/mesh/remap_topography step has been modified to remap combined topography from a cubed sphere source grid to MPAS meshes, instead of a lat-lon source grid. The weights file generation has been switched to mbtempest so that smoothing can be defined in the target MPAS mesh SCRIP file. Smoothing parameters have been added to ocean/mesh/remap_topography.cfg. This new workflow also uses a pre-build source SCRIP file stored in the bathymetry database, in addition to the combined topography file.

Checklist

• User's Guide has been updated
• Developer's Guide has been updated
• Documentation has been built locally and changes look as expected
• Document (in a comment titled Testing in this PR) any testing that was used to verify the changes

[xylar]

Before this call, we want to make sure to set descriptor.format = 'NETCDF3_64BITDATA' (Check this, it's just my best guess on the names of the attribute and its value.)

[xylar]

@bmooremaley, as we discussed, we'll need some way to support a different topography dataset for lower res regression testing. I pulled out the config options into their own config file:
#864
If we want to continue to support that 1/20 degree dataset, we would need a way to still use ESMF for that resolution. An alternative (if mbtempest if fast enough) is to use a lower resolution cubed-sphere dataset as we discussed and stick with the modified workflow you have here. I would lean slightly toward the latter so that the regression testing is using a more similar workflow to the high resolution runs.