[views] Display attributes in entity creation form based on "add" permission
Previously, the "update" permission was used. Hence in case the latter is
more restrictive that the "add" permission, an user may not be able to set
such an attribute, despite she may have "add" permission on it.
As a result of the change of permissions action in `editable_attributes`
method (add/update depending on whether the entity is being created or
modified), the "eid" attribute would have shown up in the edition form. To
avoid this, it is moved in the "hidden" section (where it should arguably
belong anyways).
Closes #4342844.
TACHES
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-- écrire objet stocke/manipule les données
-- extraire tests de chaîne de caractère
* utiliser sqlite
* écrire fonction prend chemin en argument et renvoie contenu
* extraire tests (chaîne de caractère) de spec
* utiliser yams pour schéma