✨(backend) allow to create a new user in a marketing system

We want to create a new user in a marketing system to create a dedicated
onboarding for each of them. The marketing service is implemented in the
django-lasuite library and it is possible to pick the backend we want
or implement a new one following the documentation on this library.

src/backend/impress/settings.py

@@ -328,6 +328,7 @@ class Base(Configuration):
         # OIDC third party
         "mozilla_django_oidc",
         "lasuite.malware_detection",
+        "lasuite.marketing",
         "csp",
     ]
 
@@ -808,6 +809,30 @@ class Base(Configuration):
         ),
     }
 
+    # Marketing and communication settings
+    SIGNUP_NEW_USER_TO_MARKETING_EMAIL = values.BooleanValue(
+        False,
+        environ_name="SIGNUP_NEW_USER_TO_MARKETING_EMAIL",
+        environ_prefix=None,
+        help_text=(
+            "When enabled, new users are automatically added to mailing list "
+            "for product updates, marketing communications, and customized emails. "
+        ),
+    )
+
+    LASUITE_MARKETING = {
+        "BACKEND": values.Value(
+            "lasuite.marketing.backends.dummy.DummyBackend",
+            environ_name="LASUITE_MARKETING_BACKEND",
+            environ_prefix=None,
+        ),
+        "PARAMETERS": values.DictValue(
+            default={},
+            environ_name="LASUITE_MARKETING_PARAMETERS",
+            environ_prefix=None,
+        ),
+    }
+
     # pylint: disable=invalid-name
     @property
     def ENVIRONMENT(self):