Fix issues with knowledge sources and aggregator

[caufieldjh]

Knowledge source and aggregator don't appear to be populated.
I've seen this happen with KGX before - sometimes the solution was more of a workaround with Koza, but KGX really should be able to take these as input args.
See BFO, for example:

id	category	name	description	provided_by
BFO:0000002	biolink:NamedThing	continuant		BFO_relaxed.owl
BFO:0000001	biolink:NamedThing	entity		BFO_relaxed.owl
BFO:0000003	biolink:NamedThing	occurrent		BFO_relaxed.owl

The provided_by here should not be BFO_relaxed.owl.

Similar with the edges:

id	subject	predicate	object	category	relation	knowledge_source
	BFO:0000002	biolink:subclass_of	BFO:0000001		rdfs:subClassOf	BFO_relaxed.owl
	BFO:0000003	biolink:subclass_of	BFO:0000001		rdfs:subClassOf	BFO_relaxed.owl
	BFO:0000004	biolink:subclass_of	BFO:0000002		rdfs:subClassOf	BFO_relaxed.owl
	BFO:0000020	biolink:subclass_of	BFO:0000002		rdfs:subClassOf	BFO_relaxed.owl
	BFO:0000031	biolink:subclass_of	BFO:0000002		rdfs:subClassOf	BFO_relaxed.owl
	BFO:0000006	biolink:subclass_of	BFO:0000141		rdfs:subClassOf	BFO_relaxed.owl

The knowledge source is not correct.