New metadata properties

[kba]

• dc:creator
• dc:subject
• dc:abstract
• owl:versionInfo
• schema:spatial
• schema:endDate
• schema:startDate

[kba]

I'm hesitant to add the remaining terms unless I see a concrete use case (i.e. code) that uses them. @bolandka @Dommii do we need them?

[bolandka]

Not yet, we will need them when we integrate the data for the research data ontology, however.

[kba]

Okay, just checking to make sure I didn't miss anything. Let's keep this open and I'll implement the properties once we have the assertions that need them.

[kba]

dcterms spatial repeatable

startDate, endDate plain String to make simple queries simple and complex queries possible