[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.

debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/server/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/hooks/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/sobjects/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/schemas/ usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/share/cubicweb/migration/ usr/share/cubicweb/