Bug 18474: Restore multiple holds when patron is searched for

Bug 18474: Restore multiple holds when patron is searched for

We lost the ability to place multiple holds when we are searching for
patrons. The multi_holds parameter is lost and not handled correctly in
the template.

Test plan:
- Make sure you can place multiple holds for a patron you will search for
- Same for simple hold

TODO the multiple holds view should not be displayed if only 1 record
has been selected from the search result.

Signed-off-by: claude brayer <claude.brayer@cea.fr>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>