[entity api] unify set_attributes / set_relations into a cw_set method. Closes #2423719
Allowing similar usage as create_entity/cw_instantiate.
Update cw code base to remove deprecated calls.
[workflow ui] fix state/transition edition form on existing entity. Closes #2423531
It should not return unrelated entities only in case where the entity
exists.
Also fix a deprecation warning, vocabulary values should be an
unicode string.