Bug: Ensure tor exit is disabled properly (#8863)

Simply disabling exit policies is not enough to disable an exit node, it also needs to be explicitly disabled. This may change in future versions of tor, but for now, explicitly adding 'ExitRelay 0' to the configuration is needed. This fixes #8863 (closed).

puppet/modules/site_tor/manifests/disable_exit.pp

+# ensure that the tor relay is not configured as an exit node
 class site_tor::disable_exit {
   tor::daemon::exit_policy {
     'no_exit_at_all':
       reject => [ '*:*' ];
   }
+# In a future version of Tor, ExitRelay 0 may become the default when no ExitPolicy is given.
+  tor::daemon::snippet {
+    'disable_exit':
+      content => 'ExitRelay 0';
+  }
 }