FEAT Clean useless code

apps/maarch_entreprise/actions/index_mlb.php

apps/maarch_entreprise/apps_tables.php

...aarch_entreprise/indexing_searching/search_adv_result.php

apps/maarch_entreprise/js/functions.js

apps/maarch_entreprise/lang/en.php

apps/maarch_entreprise/lang/fr.php

apps/maarch_entreprise/lang/nl.php

apps/maarch_entreprise/load_statuses_session.php

apps/maarch_entreprise/mailSignatureManagement.php

core/class/class_functions.php

migration/19.12/migrate.sh

modules/sendmail/class/class_email_signatures_Abstract.php

modules/templates/datasources/letterbox_attachment.php

modules/visa/class/class_user_signatures_Abstract.php

src/core/lang/lang-en.php

src/core/lang/lang-fr.php

src/core/lang/lang-nl.php