Requests based on using hawkBit eventing

[lizziemac]

I'm using hawkBit eventing, and noticed a couple areas for improvement:

• Target events come through with only the entity ID, and not the controller ID, and the API doesn't allow lookups. Could we either:
  • provide the controller ID in all target events
  • or allow for getting the target by the entity ID via API? neither /targets/{id} nor /targets?q=id=={id} work.
• DownloadProgressEvent events don't have any identifying information (from what I can tell). Can we add the action they are related to?
• It would be lovely to have documentation of the events