Update Bioschema namespaces to use canonical URIs

[stain]

See BioSchemas/specifications#653 -- the Bioschema namespaces should not be based at discovery.biothings.io but should be https://bioschemas.org/properties/scientificName etc. for properties (some of which still are 404 Not Found ) and https://bioschemas.org/TaxonName for canonical names for types which are not in schema.org

[multimeric]

Definitely makes sense to do this, but I'm not sure we ever got a consensus from BioSchemas on that question? At the moment I'm just pulling IRIs from their RDFS to generate the bioschemas module so once a decision is made, they (or I) can update their JSON-LD and re-run the codegen here.