Zeromq integration

Sometimes you want to send private messages from controller -> Web socket server (in a efficient manner, not just connecting to the WS server - which is slow..). Docs included.
Avoid to inject container as dependency. Inject dependencies directly.

```php

protected $zmqConfig;

protected $topicHandler;

public function __construct($zmqConfig, TopicHandlerInterface $topicHandler)
{
    $this->zmqConfig = $zmqConfig;
    $this->topicHandler = $topicHandler;
}
```