Bug 33808: Add aria-labels in opac-shelves.tt

Bug 33808: Add aria-labels in opac-shelves.tt

This patch adds an aria-label and an aria-haspopup to Download buttons
identified as non-descriptive in accessibility testing

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 429f0d6dce8e28fee5e63f06f63552775aadc543)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit c7ab9be9b0f74468b40fa322238bdffc1dcf9410)
Signed-off-by: Matt Blenkinsop <matt.blenkinsop@ptfs-europe.com>