Add run size to salmon ontology

[justinkadi]

I added "run size" term to the SALMON ontology

• label: run size
• rdfs:subClassOf http://purl.dataone.org/odo/SALMON_00000504
• definition: Number of salmon swimming upstream to spawn. This includes both harvest and escapement counts.
• skos:relatedMatch http://purl.dataone.org/odo/SALMON_00000491
• skos:relatedMatch http://purl.dataone.org/odo/SALMON_00000479

One thing I noticed is that a lot of the terms in SALMON.ttl had their definition under rdfs:comment instead of obo:IAO_0000115 like in the ARCRC.ttl. I'm not sure which to use. I also saw skos:definition being used in SALMON.ttl