Bug 12252: include item data in OAI-PMH ListRecords result

Bug 12252: include item data in OAI-PMH ListRecords result

Same in spirit to the other patch, this also includes the item detail in
ListRecords.

Test plan:
* Fetch a URL like:
http://koha/cgi-bin/koha/oai.pl?verb=ListRecords&metadataPrefix=marcxml
* Verify that there are 952 entries in the returned records where
  appropriate.

Signed-off-by: Frederic Demians <f.demians@tamil.fr>
ListRecords OAI verb returns a list of records including items in 952/995 which
are not hidden based on OpacHiddenItems syspref.

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Signed-off-by: Gaetan Boisson <gaetan.boisson@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@unc.edu.ar>