Changes to edit datatable settings

added the new external_instance enum value to the request property settings/datatables/additionalProperties/database/resource_type

added the new optional request property settings/datatables/additionalProperties/governed_by

the response's body type changed from no type to object for status 200

added the new optional request property settings/datatables/additionalProperties/reference

the request property settings/datatables/additionalProperties/database became optional

added the optional property stranded_references to the response with the 200 status

added the new optional request property deleted_datatables

added the new optional request property renames

added the new optional request property settings/datatables/additionalProperties/migrations_enabled