feat(backend): update gestionnaire creation logic and clean up DTOs

Co-authored-by: Cursor <cursoragent@cursor.com>

check_hash.js

@@ -0,0 +1,7 @@
+const bcrypt = require('bcrypt');
+
+const pass = '!Bezons2014';
+
+bcrypt.hash(pass, 10).then(hash => {
+    console.log('New Hash:', hash);
+}).catch(err => console.error(err));