Allow creation of ancestor user nodes when they are not explicitly included in a filter

JCRVLT-64 restricted the creation of user nodes only to the case when they are explicitly included in the filter. This is in practice more secure but one should also have the option to lower this guard and be more robust.

The use case I have in mind is creating exact replicas of user content in two instances. There is no security concern that users are autocreated as in the end the goal is to have identical instances.

We could have an option to allow autocreation of user nodes as this will make user creation more aligned with regular node creation.