Bug 26613: Fix it-IT unimarc_framework.sql installer file

Bug 26613: Fix it-IT unimarc_framework.sql installer file

This is really an installation issue, though at the
time of installation it did not result in any error.

During cataloguing in the items menu the "Type of item or material"
is not constrained by the itemtypes authorised_values (as it is for 942c records).

I have added the itemtypes to the installer sql in unimarc_framework.sql
as well as adding the description of this field for OPAC, which had been left empty.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>