Feature/vhirl 13


Netcdf subset service.

AC: creating netcdf subset from dataset. Add Onshore only Bouguer Geodetic Layer, Select map, download file.

Should not break code.

Needs the netcdfsubsetservice change to portal-core (commit 3c8c233b7368dd0343bbd3a3ec58f028171b04da)

Size estimation currently unavailable.