Once we have the Kafka Producer, that writes the ACK related data to a topic, and a consumer that receives those values, let's remove the exiting code:

https://github.com/aerogear/aerogear-unifiedpush-server/blob/GSOC_2017_kafka/jaxrs/src/main/java/org/jboss/aerogear/unifiedpush/rest/registry/installations/InstallationRegistrationEndpoint.java#L230

So that the counter is only based on Kafka