Bug 12726: Show RDA tag 264 on OPAC Results XSLT view (MARC21)

Bug 12726: Show RDA tag 264 on OPAC Results XSLT view (MARC21)

This patch adds the same information to the Publisher line of OPAC Results
as bug 12724 did on OPAC Detail.
To accomplish this and reduce repeated code, two XSLT routines (named
templates) are moved from OPACDetail to MARC21slimUtils.

Test plan (see also bug 12742 and the rules mentioned there):
[1] Add tag 260 and some 264s to your MARC21 record.
[2] Check the display of OPAC Details. Should not have changed.
[3] Now check also the display of this record in OPAC Results.
[4] Change some indicators in the record. Check OPAC Results again.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
On top of 12724, no change on detail, more data on results.
No koha-qa errors

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Change moves display logic to Utils, 260 will display as
before and 264 will only display if there is no 260.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>