Support 'recommended' fields on a model card schema

[GCHQDeveloper36]

Is your feature request related to a problem? Please describe.

Model card schemas define the fields an organisation would like the owners/developers to consider, but there isn't any way to enforce/require/suggest which fields are 'required' vs 'optional'. Therefore when a release is created, and a reviewer considers the card, there might be some key information missing that's needed to make an informed decision.

Describe the solution you would like

Some sort of modification to the schema definitions to allow for annotating fields if they're "required"/"recommended" (wording TBD). I'd imagine that from an end-user perspective, we could highlight "recommended" fields during an edit session, and allow the list of (missing) fields to be seen in a simple list when a collaborator views a model card.

Describe alternatives you have considered

I think jsonschema supports 'required' fields, however when a card is strictly validated, these would get flagged and defeat the point of the living, editable card. Extending the support for jsonschema, or ignoring 'required' fields in a validation response, might be needed.

[JR40159]

Hi, thanks for raising this. Something we've already been considering is introducing the ability to configure mandatory fields for lifecycle states. This would enable the requirements of a model card to increase as it moves through it's lifecycle. Would be interested to know your thoughts on this, thanks.

[GCHQDeveloper36]

That could definitely work too, although does that start to break the separation of model card schemas + core system code? Since the states are defined in system configuration, but schemas are considered 'separate' at the moment?

[JR40159]

I don't think it is too problematic considering both aren't hard-coded however, we could consider defining the states in model schemas so that they're defined and used in the same place? This could work quite well if different types of model cards are likely to have a different set of states.