feat: sample codes

[cmdoret]

This is a first experiment with using dynamic enums to describe the range of a property. This does not appear to enforce much in the generated code, but my understanding is that (at least for now) this is mostly descriptive.

In our case, it should be OK as we control data entry.

The relevant change is in src/modos_schema/schema/modos_schema.yaml
It adds dynamic enums for cell types (cell ontology) and biological source material (uberon).

[rmfranken]

Must: take a look at the sh:in's generated for SHACL
probably nice: See why you are generating sh:nodeKind restrictions that may not be needed
pretty: regex's to further restrict some string props

[cmdoret]

Thanks, @rmfranken based on your inputs I've switched to making the values uriorcurie instead of using dynamic enums, and also enforced it for taxon ids (instead of integers).