fix: allow to query bogus model as ``worklow_instances`` that do not have ``active`` field.
fix: remove default limit to search (which is applied by default to ``all()``)
fix: should cast an AttributeError so that ``getattr()`` can be used with a default value.
fix: remove arbitrary limit when using filter.

It should be added this limit could not be removed easily due to the fact that
providing 'None' or '0' was ignored due to the ``if int(limit)`` barrier.