Add container-inspect step after seeing "start" events

In the Docker event listener, after we see a container "start" event for our supported images, we fire a couple event emitters and update context values, but we need to also make container inspect requests to get host+port configurations to inform the sidecar what the Kafka + Schema Registry configs are.

We're getting by now because we only focus on one Kafka image and one Schema Registry image, so we largely know the configurations of each. Once we move to `DIRECT` connections, we'll need more information about each container to update those connections.