[repository] add an ``internal_cnx`` method to replace ``internal_session`` Accessing the repo through a Session is deprecated. We need an easy replacement for ``internal_session``. This API change was a good occasion to stop disabling integrity hook by default. This is huge source of bug in user-code. related to #2503918

Essayer le champ de recherche. Essayer des recherches comme "fiche
unmotachercher", ou encore "fiche wikiid index" ou "345".