Allow the registration of a message listener via a connection when done within an ManagedExecutorService.

Currently, you cannot call setMessageListener when a connection is running with in an application server. I believe we can circumvent this limitation if the registration of the underlying threads is done via a ManagedExecutorService. The spec should be updated to indicate that an implementation should register the delivery code via a ManagedExecutorService.
#### Affected Versions
[2.0]

Start by reviewing the setMessageListener restriction and the proposed use of ManagedExecutorService in the Jakarta Messaging specification. Determine which specification text and implementation expectations would need to change for message-listener registration in an application server, and define done as an agreed, precise specification update.

Written by the indexing model from the issue text.