Bug 7818 Add UNIMARC biblio records zebra DOM def files

Bug 7818 Add UNIMARC biblio records zebra DOM def files

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
I tested two UNIMARC Koha installations using the sample UNIMARC
data from the BibLibre sandbox, comparing the results with DOM
and with GRS-1 indexing. The results are very similar, though there
are some differences. Most noticeable:
* relevance and facets seem to be more accurate with DOM enabled
* the GRS-1 configuration returns approximately 10% more results with
  random single keywords like "petit," but the DOM results contain
  the most relevant items, and any lacks in the configuration can
  easily be corrected as UNIMARC users identify fields that should be
  indexed but aren't
* authority-controlled searches match exactly
* author and topic facets do not work with the out-of-the-box GRS-1
  indexing configuration (?!?)
(adding second sign-off line below because all that probably looks like
a commit message and not a sign off)

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>