Enable HDFS for deep storage

[adwk67]

As a user of druid services I want to be able to use HDFS for deep storage.

Using local storage for deep storage only works if the storage location is reachable by all relevant druid services (middle-manager, historical server).

• This would be possible with e.g. Persistent Volume and Persistent Volume Claims, but would only realistically be used for prototype/demo cases
• a better solution is to use HDFS and deactivate local-deep-storage as we should offer HDFS anyway, and it lends itself more easily to integration testing (using our own operator).