vf:property instead of vf:relationship

[ahdinosaur]

from #37 (comment),

@elf-pavlik: How about s/relationshipType/relationshipProperty/ or even simply using for now vf:property seeing when we really need
vf:relationshipProperty rdfs:subPropertyOf vf:property ?

this is an interesting idea, so here's a dedicated issue for discussion.

[elf-pavlik]

@ahdinosaur since this Relation(ship) design pattern seems not specific to Agent, can we take it to https://github.com/valueflows/valueflows/issues/63 ?

[ahdinosaur]

@elf-pavlik yes 👍