Various fix and improvements re User authentification

config/services.yaml

src/Admin/InteractionConfigurationAdmin.php

src/Controller/ElementFormController.php

src/DataFixtures/MongoDB/LoadConfiguration.php

src/Document/Configuration.php

src/Document/FeatureConfiguration.php

src/Document/InteractionConfiguration.php

...tes/bundles/FOSUserBundle/Registration/register.html.twig

templates/element-form/contributor-login.html.twig