need to future proof the versions of unitsSchema and coordinateSystemSchema

[jvandegriff]

We have a list of enumerated items for the units and coordinates system schemas, and these reference very specific versions of a standard, and some of these have been updated recently so the HAPI spec is out of date, and we don't want to be updating the list every time.

Even we have spase2.4.1, which seems way too specific. And SPASE is at 2.7.something right now.

So we could allow compatibility across final digits of semantic versioning (units with 2.4.1 should be compatible with 2.4.2 or 2.4.6, etc)

For HAPI, we need a way for data providers to indicate which version of the schema was used to make the units strings or coordinate frame names.

VOUnits has an antler schema, which needs coding to implement (along with the other constraints)
https://www.ivoa.net/documents/VOUnits/20231215/REC-VOUnits-1.1.html#tth_sEcC.4