Message Retention for un-delivered messages

### Is your feature request related to a problem? Please describe.
Due to network glitch will the server hold the message and till what duration until it is purged

### Describe the solution you'd like
Providing Message Retention configurable attribute, because not all scenarios require message retention feature while some scenarios require message retention feature especially when the request is transactional in nature

### Additional context
Providing slider or number field to configure the messages retention

No files, tests, or entry points are named. First clarify the retention semantics for undelivered messages, including the purge duration and how the configurable value should be exposed; done means an agreed configuration and documented behavior for transactional and non-retained scenarios.

Written by the indexing model from the issue text.