Produce a complete ONIX record

[ja573]

At present we output ONIX files based on the specifications provided by each platform, which are often incomplete. We should produce a complete record that implements our data model in full, and output it under onix_3.0::thoth

[rhigman]

Task list:

• Create infrastructure based on an existing ONIX output
• Incorporate any additional features present in other ONIX outputs
• Convert from one <Product> per Work to one <Product> per Publication
• Go through Thoth data model to identify fields not yet output
• Add new fields under Work
• Add new fields under existing relations, i.e. Imprint, Contribution, Publication, Funding, Series...
• Add new fields to represent new relations, i.e. Reference, Related Work...
• Make notes and report back on any Thoth fields which are not (fully) supported by ONIX
• Check for any fields which are mandatory in ONIX but optional in Thoth, and determine how to handle them
• Determine how to handle existing fields with hard-coded outputs (e.g. Audience, not supported in Thoth): should they be retained (to maximise ONIX completeness) or removed (to closely reflect data model)?
• Update unit tests to reflect new format

[rhigman]

Make notes and report back on any Thoth fields which are not (fully) supported by ONIX

data model comparison.odt

Now also under new NextCloud ONIX folder