Standardize Dead Letter Queues

JMS 2 made the JMSXDeliveryCount property required. However, dead letter queues remain non-standard although they are widely implemented and used. As a result, JMS application portability is needlessly limited and the feature is harder to use (often requiring digging around vendor documentation).

This proposal is to standardize the concept of dead letter queues and make them available at a standard location - e.g. java:comp/deadLetterQueue.

No source files, tests, or entry points are named. Start by reviewing the Jakarta Messaging specification and existing vendor dead-letter queue conventions, then determine the scope for standardizing a common location such as java:comp/deadLetterQueue and define how completion would be verified.

Written by the indexing model from the issue text.