Bug 6536: Include SRU searching in Breeding.pm

Bug 6536: Include SRU searching in Breeding.pm

This patch makes it possible to include SRU servers in Z3950 search.
It adjusts the Z3950Search routine in Breeding module.
It also replaces SQL code with DBIx statements in Breeding.pm/Z3950Search
and the associated scripts z3950search.pl in cataloguing and acqui.

Test plan:
Verify if a normal Z3950 search still works in cataloging/acqui.
Add a SRU target. (You could just use Koha's port 9998.)
Define sru_options like sru=get.
Use that target in a Z3950 search in cataloging and acqui. (Import.)
Test sru_fields translation by comparing search results between various
settings for some of the fields. For instance, leave title empty and
after that set it to the title field of your SRU target.

Signed-off-by: Giuseppe Angilella <giuseppe.angilella@ct.infn.it>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>