Round trip test examples from RDF via JSON schema and JSON-LD and SHACL

[rob-metalinkage]

example data from TTL should be serialisable in JSON-LD, conform to generated JSON schema.

Likewise JSON data conforming to schema should be parseable as JSON-LD and conform to SHACL constraints.

Challenge is the many flavours of JSON-LD compaction and JSON object containment in real world data - in fact schemas need to be wrapped in containers in many cases and derived implementations be compatible with such patterns.

The JSON world has not yet matured enough to make the nature and viability of these patterns clear.