feat: use RfcAuthor for red API

[jennifer-richards]

Changes the RfcAuthor schema to match the RfcAuthor model and returns data from doc.rfcauthor_set if that is not empty. Otherwise, it uses doc.documentauthor_set data. The same serialized schema is used regardless of the data source.

The new schema is below. Note that titlepage_name is the only guaranteed non-empty field. This is the only name field included - the old name field has been dropped. A new datatracker_person_path field is added. This is the URL path for the author's "person page", relative to datatracker's root. If this is empty, no link should be rendered.

When representing a DocumentAuthor:

• titlepage_name will be person.plain_name() (same value as the name field prior to this refactor)
• is_editor is always False
• person is always non-null

    RfcAuthor:
      type: object
      description: Serializer for a DocumentAuthor in a response
      properties:
        titlepage_name:
          type: string
          maxLength: 128
        is_editor:
          type: boolean
        person:
          type: integer
          nullable: true
        email:
          type: string
          format: email
        affiliation:
          type: string
          description: Organization/company used by author for submission
          maxLength: 100
        country:
          type: string
          description: Country used by author for submission
          maxLength: 255
        datatracker_person_path:
          type: string
          format: uri
          description: URL for person link (relative to datatracker base URL)
      required:
      - titlepage_name

[holloway]

Looks good, assuming that get_absolute_url does return a path and not a full url

[jennifer-richards]

Looks good, assuming that get_absolute_url does return a path and not a full url

Yes, it returns only the path. I don't know why it's named that way but it's Django's convention. (We supply the method so it won't change on us.)