Add a HTTP endpoint for health check

[rajan-github]

Enable a HTTP PORT for Health check. We are configuring websocket port using following configuration-

public SocketIOServer socketIOServer() {
        Configuration configuration = new Configuration();
        configuration.setHostname(hostname);
        configuration.setPort(port);
        return new SocketIOServer(configuration);
    }

But currently, there is no health check endpoint available on configured PORT. Can we please add a health check endpoint to enable library to support liveness probe and readiness probe under kubernetes deployment. @mrniko @unverbraucht

[NeatGuyCoding]

I think the framework like spring-boot, quarkus, micronaut already provided the /health endpoint, you can just implment the health indicator within your framework environment to check the SocketIOServer health metrics (like the ops of messages and last message sent time, and etc.)