Use natural sort for required fields.

Closes #1838 (closed).

• Publication index designation field
• artifacts/composites designation field
• Publication view (in the artifact table below) designation, exact ref
• Artifact view (seal / impressions / composite / witness accordion) designation
• https://cdli.mpiwg-berlin.mpg.de/admin/entities-publications/add/publication/artifacts/432291 designation, exact ref