Metadata validation

[marcolarosa]

• add a control to pick ro crate version to conform to
• validate metadata to confirm it meets the absolute minimum requirements of that ro crate version:
  • name, description datePublished, publisher etc (TBD)
  • checks entity ids are sensible and as expected: ORCID etc
• if a profile is in use, validate metadata against the profile selection to ensure all required properties have input