Support returning single complex query in get_filter_predicate instead of only supporting dictionary

[jxltom]

I would like to override get_filter_predicate without rewriting the whole filter function such as for MultipleChoiceFilter, it will be nice to support get_filter_predicate returning a single complex query.

For now, only format like {question__startswith='Who'} is accepted, it would be nice to support returning something like Q(question__startswith='Who') | Q(question__startswith='What') directly from get_filter_predicate.