Improve datatype of runs:platform to OntologyTerm

[joerivandervelde]

The datatype of runs:platform could be changed from String to OntologyTerm, using as value range the terms listed under https://www.ebi.ac.uk/ols/ontologies/genepio/terms?iri=http%3A%2F%2Fpurl.obolibrary.org%2Fobo%2FGENEPIO_0000071. That would make the data more interoperable. In case the data doesn't fit, perhaps null flavors could be used (https://raw.githubusercontent.com/fairgenomes/fairgenomes-semantic-model/main/lookups/NullFlavors.txt), or a new term introduced locally.

[mbaudis]

@joerivandervelde I guess this was left open (as string) since no good ontology branch for diverse platforms exists - e.g. the one you link to is very incomplete and specific for sequencing platforms.

As with your other issues you posted today: Yes, these could be implemented (as even indicated for some ...) but then need some broadly working examples. See e.g. platformModel. So feel free to craft a PR ... Generally: ontology terms/trees are suggested in the description.