Bug 14790 - Add OPAC view link to Serials detail

Bug 14790 - Add OPAC view link to Serials detail

Test Plan:
1) Apply this patch
2) Browse to subscription-detail.pl for a given serial
3) Note the new "OPAC view" link
4) Click the link, a new tab should open up showing the record
   details for that record in the OPAC

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit 600786e7f1d0577a50f154ffead7b89f3505c977)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>