No QoS profiles supported

The `ros2-web-bridge` doesn't support QoS profiles for the creation of subscribers. Therefore, the standard QoS profile is used (uses KEEP_LAST with a depth=10). The `ros2-web-bridge` is based on `rclnodejs`, which supports QoS profiles. Hence, it can fixed in the [subscription_manager](https://github.com/RobotWebTools/ros2-web-bridge/blob/develop/lib/subscription_manager.js#L57).