This patch moves the Koha::Biblio->adopt_items_from_biblio method to the
Koha::Items set class and updates all calls from
Biblio2->adopt_items_from_biblio(Biblio1) to Biblio->items->move_to_biblio(Biblio2)
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>