[PBI] Add custom TTL for dynamic topics

[devkelley]

Description

Currently, the topic timeout notification is sent every 60 seconds. This would change to allow the publisher to set a custom timeout length. This length could be set to infinite with -1. During the course of adding this feature the topic action returned to the publisher should be TIMEOUT rather than STOP

Acceptance criteria

• TTL can be set by publishers
• TIMEOUT flag is added as return option from the pub sub service