Bug 6874: Attach files to bibliographic records

Bug 6874: Attach files to bibliographic records

New cataloging plugin upload.pl and new system preference 'uploadPath'.

upload.pl provide a way to upload files on the server and store a link
(url) to it in MARC
uploadPath is the absolute path on the server where the files will be
stored. It's possible to have a hierarchy of directories under this path
and the plugin will allow to choose in which directory to store the
file.
Stored value in MARC subfield looks like this:
<OPACBaseURL>/cgi-bin/koha/opac-retrieve-file.pl?id=<SHA-1 of the file>
So both 'uploadPath' and 'OPACBaseURL' sysprefs have to be set for this
plugin to work correctly

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Slightly amended/simplified the patch during QA: The changes to
GetMarcUrls are not really needed, and would have needed some
attention. Another link text can be supplied by the plugin too.

This also reduces the need for changes in basket.pl,
MARCdetail.pl, detail.pl, opac-basket.pl and opac-detail.pl.
Signed-off-by: Tomas Cohen Arazi <tomascohen@unc.edu.ar>
Edit: more meaninfull commit subject