Log config object deletions to replay log

The initial config object sync for each new connection (in
`ApiListener::SendRuntimeConfigObjects()`) only considers currently
existing objects and has no way to pass the information that objects
were deleted in the meantime.

This commit logs config object deletions to the replay log if required
so that there is a chance that it will be propagated to nodes that were
offline when the deletion happened.

Note that this can only be considered a workaround as the replay log
might be pruned or could even be completely disabled. Also, there still
seems to be a race-condition between the config sync and replay log of
multiple new connections at the same time.

lib/remote/apilistener-configsync.cpp

@@ -423,7 +423,7 @@ void ApiListener::DeleteConfigObject(const ConfigObject::Ptr& object, const Mess
 		if (!target)
 			target = Zone::GetLocalZone();
 
-		RelayMessage(origin, target, message, false);
+		RelayMessage(origin, target, message, true);
 	}
 }