Make inclusion_notification_feature site-wide

src/lib/Sympa/Config/Schema.pm

@@ -2576,7 +2576,7 @@ our %pinfo = (
     ### Data sources page ###
 
     inclusion_notification_feature => {
-        context => [qw(list)],
+        context => [qw(list site)],
         order   => 60.01,
         group   => 'data_source',
         gettext_id =>