BibIndex: bibauthorid performance improvements

* Re-implements get_author_canonical_ids_for_recid() to bypass
  complex BibAuthorID API usage and directly retrieve data
  from the DB for a gain of speed of ~800x.

Signed-off-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Co-authored-by: Alessio Deiana <alessio.deiana@cern.ch>
Co-authored-by: Samuele Carli <samuele.carli@cern.ch>