Map SpatialDataServiceCategory to serviceCategory

[barthanssens]

The XSLT already has a SpatialDataServiceCategory param for a mapping to geodcatap:serviceCategory, but it looks to be unused.

GeoDCAT-AP 3.1.0 mentions /identificationInfo/descriptiveKeywords/keyword and/or identificationInfo/descriptiveKeywords/Type`

In a real-life example I've seen this

      <gmd:descriptiveKeywords>
            <gmd:MD_Keywords>
              <gmd:keyword>
                <gmx:Anchor xlink:href="http://inspire.ec.europa.eu/metadata-codelist/SpatialDataServiceCategory/infoFeatureAccessService">infoFeatureAccessService</gmx:Anchor>
              </gmd:keyword>
              <gmd:keyword>
                <gco:CharacterString>infoFeatureAccessService</gco:CharacterString>
              </gmd:keyword>

[laers]

I also notice that dcat:DataService has geodcatap:serviceType which points to the INSPIRE codelist http://inspire.ec.europa.eu/metadata-codelist/SpatialDataServiceType