Define scope and output of SHACL validation process

[rob-metalinkage]

A process to validate RDF files with SHACL rules has been provided. This fails for mapping files - and does not yet report validation results as artefacts (only action pass or fail).

Consider ideal scope (which files to validate) and reporting outputs - generate an example report and bring to SOSA meeting with a proposal.

[rob-metalinkage]

Need to decide if SHACL rules for enforcing rules in specification text are part of this activity or will be handled by implementations such as https://github.com/opengeospatial/ogcapi-sosa/