Improve the ontology annotation with matching from SKOS

[Ludee]

Description of the issue

SKOS offers standardized terms
https://www.w3.org/TR/skos-reference/#mapping

Ideas of solution

skos:mappingRelation
skos:closeMatch
skos:exactMatch
skos:broadMatch
skos:narrowMatch
skos:relatedMatch

"isAbout": [
              {
                "name": "",
                "@id": "",
                "mappingRelation": ""
              }
            ],
"valueReference": [
              {
                "value": "",
                "name": "",
                "@id": "",
                "mappingRelation": ""
              }
            ]

Workflow checklist

• I am aware of the workflow in CONTRIBUTING.md

[Ludee]

"isAbout": [
              {
                "name": "wind farm",
                "@id": "http://openenergy-platform.org/ontology/oeo/OEO_00000447",
                "mappingRelation": "skos:closeMatch"
              }
            ],
"valueReference": [
              {
                "value": "onshore",
                "name": "onshore wind farm",
                "@id": "http://openenergy-platform.org/ontology/oeo/OEO_00000311",
                "mappingRelation": "skos:exactMatch"
              },
              {
                "value": "offshore",
                "name": "offshore wind farm",
                "@id": "http://openenergy-platform.org/ontology/oeo/OEO_00000308",
                "mappingRelation": "skos:exactMatch"
              }
            ]

[stap-m]

Make skos:exactmatch the default value?