✨(email) white brand email

The email was branded "La Suite Numérique",
we updated the template to make it generic, we
will use settings env variables to customize the
email for each brand.

src/backend/impress/settings.py

@@ -352,9 +352,11 @@ class Base(Configuration):
 
     # Mail
     EMAIL_BACKEND = values.Value("django.core.mail.backends.smtp.EmailBackend")
+    EMAIL_BRAND_NAME = values.Value(None)
     EMAIL_HOST = values.Value(None)
     EMAIL_HOST_USER = values.Value(None)
     EMAIL_HOST_PASSWORD = values.Value(None)
+    EMAIL_LOGO_IMG = values.Value(None)
     EMAIL_PORT = values.PositiveIntegerValue(None)
     EMAIL_USE_TLS = values.BooleanValue(False)
     EMAIL_USE_SSL = values.BooleanValue(False)