new metadata field ‘Data coverage reference’

[stufraser1]

Add new metadata field, for layer used in TH! Called ‘Data coverage reference’.

This would contain standard text referring to the coverage of the data, e.g., ‘National’. This field would be extracted with the data owner and/or layer title using the Geonode list views, and built into scripts to update the shp and geojson map file (by GFDRR).
Update on TH would still have to be via github request, but this would streamline update process on admin side.

[stufraser1]

@ErikKBethke developing an automated process which will leverage this.