BibIndex: consistency check optimizations

• Amends the way we check for index table consistency during indexing of search index and ranking tables by amending slow queries and replacing them with more appropriate lightweight queries. (closes #1436)

• Updates tabcreate.sql and BibIndex admin adding a key index on "type" column.

• Creates a DB schema upgrade script for existing installations.

Co-authored-by: Alessio Deiana <alessio.deiana@cern.ch>
Reviewed-by: Samuele Kaplun <samuele.kaplun@cern.ch>