Re-migrate concept->reference nodes with default values

[johnatawnclementawn]

• capture default values configured for concept nodes now that reference datatype supports default values
• update problematic modeling issues to be enumerated here:
  • Nodegroups with a label/statement and corresponding language (e.g. appellative_status_ascribed_name_language) should use the non-localized string datatype for the label/statement and a single-select reference datatype for language
  • Concepts should only participation in one scheme - Part of Scheme should be cardinality-1 and a single-select resource instance node