Bug 26655: Add ARIA Labels to OPAC Lists

Bug 26655: Add ARIA Labels to OPAC Lists

This patch adds ARIA labels to opac-shelves.tt
so that checkboxes for list items are meaningful
to users of screenreaders and other assistive
technology.

Test Plan:
1/ Open an OPAC list
2/ Inspect the checkbox for a list item
3/ Confirm the aria-label is missing
4/ Apply the patch
5/ Refresh the Opac list page
6/ Inspect the checkbox for a list item
7/ Note that there is now an aria-label with a
meaningful description
8/Sign off

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>