[optimization] improve massive write performance by optimizing hooks selection
profiling on some massive deletion showed up that 2/3 of the time was spent
in hooks selection. Those changes make it much more acceptable (through
selection is still not negligeable):
* use one registry for each event, so we've much less hooks to check
when emiting an event as well as no more need for the match_event
selector. This required ability to put one appobject
into several registries, using a __registries__ class attribute.
* check for deprecated .enabled at registry initialization time instead
of at selection time
A very simple HooksManager class has been reintroduce to choose the
right registry on call_hooks.
Those optimisations leads to a ~x3 factor of time necessary to delete
16000 entities.