Allow async data to be invalidated by notification filter preference change

Notification filter preferences are currently saved in a custom DB and not in documents so the async rendering mechanism is not called at all whenever those data changed. In general the data don't have impact on the rendering of the pages so it's ok, except for the UI related to the administration of those data and for computation of the watch page status: we cannot make those async / cache because there's an invalidation problem.

We'd need to add some APIs to allow those data to be invalidated when modified so that we can start using async / cache in the various UIs using them.