LP#1979071: (follow-up) fix various DB schema and update issues

LP#1979071: (follow-up) fix various DB schema and update issues

* Incorporate the delayed reification option for search dictionary
  updates derived from authority records (see bug 1997485)
* Fixed an issue that prevented propagation of changes to main
  headings
* Fixed an issue introduced in bug 1977485 that prevented
  authority headings from being deleted
* Remove now-disused authority.indexing_ingest_or_delete()
* Remove an older version of authority.propagate_changes()
  from the base schema; this would be an issue in new databases
  installed from scratch.

Signed-off-by: Galen Charlton <gmc@equinoxOLI.org>