BibAuthority: initial release

* BibAuthority: New module containing utility functions,
  configuration and tests.  Adds demo records and new
  index tables.  Adds HowTo guides for admin and hacking pages.
  (closes #1602)

* BibIndex: When indexing authority-controlled subfields
  of bibliographic records, enrich the index with terms
  from a configurable list of subfield values from the
  referenced authority record.

* BibIndex: When looking for recently changed bibliographic
  records to re-index for a given authority-controlled subfield,
  reindex all bibliographic records that contain references
  towards recently updated authority records, even if the
  bibliographic records in questions have not been recently updated.

* BibFormat: Simple HTML for authority record.  Links for
  browsing between dependent authority and bibliographic
  records.

* Other modules: some modifications in other modules as well.

Co-authored-by: Grzegorz Szpura <grzegorz.szpura@cern.ch>
Signed-off-by: Grzegorz Szpura <grzegorz.szpura@cern.ch>
Tested-by: Tibor Simko <tibor.simko@cern.ch>