Bug 18403: Add new methods Koha::Patrons->search_limited and use it where needed

Bug 18403: Add new methods Koha::Patrons->search_limited and use it where needed

Most of the time when we search for patrons we do not want to search for all patrons,
but just the ones the logged in user is allowed to see the information.
This patch takes care of that by adding a new search_limited method to Koha::Patrons.
When called this method only search for patrons that the logged in user is allowed
to see.

Test plan:
Patron autocomplete search should be limited

Signed-off-by: Signed-off-by: Jon McGowan <jon.mcgowan@ptfs-europe.com>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>