refactor Dataset.json

[zopalmer14]

Summary

Should resolve: #43

Documentation: Dataset

Notes

• accrualPeriodicity - Frequency class issue is being addressed in a separate PR (currently draft)
• I'll make another commit that fixes the formatting/styling using Prettier, then will move the PR from draft to ready.

Changes:

• contactPoint - change to mandatory; remove option for null value; add to required array
  • James - Even if the data resource isn't accessible to the public, knowing where to direct a FOIA or other request is important information for the public
  • It's already required at the Dataset level in DCAT-US 1.1, so no backward compatibility issue
• identifier - change to mandatory; remove option for null value; add to required array
  • Identifiers are essential for Data.gov and are already required at the Dataset level in DCAT-US 1.1
• keyword - remove "minLength": 1 restriction. Do we know why this was included?
• next / nextVersion - in documentation but missing from jsonschema; add to jsonschema; mirror prev / previousVersion schema
• rights - change to an array; matches documentation and makes sense given the property's usage as a catch-all for legal related metadata that is not covered by accessRights or license

Discussion Topics

• Many properties are in jsonschema but are not in documentation - 49 properties in documentation; 58 in jsonschema
  • Properties: supportedSchema, first, hasCurrentVersion, created, rightsHolder, hasPart, replaces, wasAttributedTo, wasUsedBy
  • I think these are dcat:Resource properties (at least some) and five of them can be found in the documentation for other related classes (i.e., DataService.created, DataService.rightsHolder, DataService.wasUsedBy, DataSeries.first, and Catalog.hasPart).
  • Do we want to support them? I think some of them make more sense than others for use with Dataset, but I know we've generally aired on the side of leaving extra properties in case someone wants to use them.
• Undefined or unavailable controlled vocabularies (CVs)
  • status - accepts a Concept object or string IRI; CV (VOCAB-ADMS-SKOS) has an unresolvable URL
    • Should we just leave it as is, or implement the CV
      • MUST take one of the following values: Completed, Deprecated, Under Development, Withdrawn
  • theme/category - DATA-GOV-THEME
    • For backwards compatibility, switch to a simple string rather than Concept
  • accessRights - DATA-GOV-AR
    • For backwards compatibility
      • Switch key/name to accessLevel (DCAT-US 1.1)
      • Switch to the old DCAT-US 1.1 options: public, restricted public, non-public

[zopalmer14]

I'm going to break this PR up into smaller ones that are oriented around the specific changes (e.g., an identifier PR, a contactPoint PR, a consistency between classes PR) and will also create issues around some of the discussion items. Will close once done.