Calling business logic in a factory is a code-smell, because it
usually requires the object to be saved into database, and may have
unintended consequences when the business logic is changed.
Also, this allows to just build a published procedure, without saving it
to the database.
On the 22/01/2020, a technical error on the demarches-simplifees.fr
instance made us delete some files attached to some dossiers.
This PR adds a warning when browsing a dossier containing attachments
that were deleted.
