Add interface for MD_FeatureCatalogue

[desruisseaux]

The FeatureCatalogueDescription currently has two direct subtypes: CoverageDescription (itself specialized with ImageDescription) and FeatureCatalogueDescription. But there is another type not yet provided by GeoAPI: FeatureCatalogue. This class is documented as "a catalogue of feature types" and contains only one property: featureCatalogue of type FC_FeatureCatalogue (from ISO 19110), documented as "the catalogue of feature types, attribution, operations, and relationships used by the resource" (cardinality 1:N). This class has not been made available in GeoAPI because its only property is a dependency to ISO 19110, which is not yet available in GeoAPI.

If this interface is added in GeoAPI, then @code FeatureCatalogue in FeatureCatalogueDescription should be changed to @link FeatureCatalogue.