Import SKOS mapping relations #636

[l-emele]

Summary of the discussion

This PR imports SKOS mapping relations. The replacement of the current use of may be identical to annotations will be done in a follow-up pull request.

Type of change (CHANGELOG.md)

Add

• skos:closeMatch
• skos:exactMatch
• skos:relatedMatch

Workflow checklist

Automation

Part of #636

PR-Assignee

• [ ] 🐙 Follow the Pull Request Workflow
• [ ] 📝 Update the CHANGELOG.md
• [ ] 📙 Add #'s to term tracker item

Reviewer

• [ ] 🐙 Follow the Reviewer Guide
• [ ] 🐙 Provided feedback and show sufficient appreciation for the work done