Include instance id in the inventory-storage notifications for items

Background

Apache Kafka should be used directly in inventory-storage for implementation of domain event pattern, which is needed for both remote-storage integration and the new search module. This direct usage of Apache Kafka should be considered as a special case, as it was for data-import. Also, it is a special case, that storage modules use more than one data storage. For the search module, the performance is significant. Kafka partitioning provides the system with an out-of-the-box mechanism for scaling out modules.
Action items

• Add instance_id to inventory-storage update notifications.