Configure QueueBrowser's pulsar reader with subscription name

[michaeljmarshall]

QueueBrowser connects to Pulsar using a Reader. A reader looks like a normal consumer from the pulsar protocol perspective. It is associated with a subscription name, which is later used by the authorization framework to determine if the client's role has permission to perform the action on the subscription, even though the subscription is not technically used. Therefore, we need to make sure we can configure the subscription name if we're connecting as a non-admin role.

[michaeljmarshall]

@eolivelli - this passes tests locally now, for me. My one higher level concern is whether https://github.com/datastax/pulsar/pull/246 will break any other components that rely on readers. Does the JMS implementation for transactions have any dependency on them?