Bug 31699: Add 'return' option to opac modal login

Bug 31699: Add 'return' option to opac modal login

This patch adds the option to trigger a redirect back to the current
context after successful login using modal logins triggered from various
places in the OPAC.

To make use of this, simply add 'data-return="true"' to the modal trigger link.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 507d48413d3d09866a37db81d2a856f9a0a7c6f9)
Signed-off-by: Jacob O'Mara <jacob.omara@ptfs-europe.com>