Bug 25303: Make Koha::Objects->delete loop on the object set

Bug 25303: Make Koha::Objects->delete loop on the object set

If we call Koha::Libraries->delete but Koha::Library->delete exists
(ie. Koha::Object->delete is overridden), then we Koha::Objects->delete
will be called and the overridden will not be executed.

This patch suggests to test if the method is overridden (using
Class::Inspector->function_exists). If so we loop on the different
objects of the set in a transaction and call the overridden ->delete method.

Existing tests widely cover this change.
t/db_dependent/Koha/Objects.t
    subtest 'Return same values as DBIx::Class' => sub {

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>