Bug 17499: Define koha_object(s)_class where needed

Bug 17499: Define koha_object(s)_class where needed

This patch adds koha_object(s)_class for needed modules
to fix issues with tests.

Sponsored-by: Koha-Suomi Oy
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Sam Lau <samalau@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>