Geo-coverage support for semi-structured content like DCAT or DC

[huberrob]

There should be a helper to parse semi or unstructured geo-coverage info e.g. from DC or DCAT. see:

Dublin Core (as DCSV):
https://www.dublincore.org/specifications/dublin-core/dcmi-point/
https://www.dublincore.org/specifications/dublin-core/dcmi-box/
and
https://www.dublincore.org/specifications/dublin-core/dcmi-dcsv/

DCAT
https://www.w3.org/TR/vocab-dcat-3/#Property:dataset_spatial
https://www.w3.org/TR/vocab-dcat-3/#Class:Location
https://www.w3.org/TR/vocab-dcat-3/#Property:location_geometry

"The range of this property (locn:Geometry) allows for any type of geometry specification. E.g., the geometry could be encoded by a literal, as WKT (geosparql:wktLiteral [GeoSPARQL]), or represented by a class, as geosparql:Geometry (or any of its subclasses) [GeoSPARQL]."