Add a dead letter queue (DQL) implementation

[astubbs]

Implemented as a draft extention of termainl retry handling:

https://github.com/astubbs/parallel-consumer/pull/8

Extension of:

• #242

Related:

• https://github.com/confluentinc/parallel-consumer/issues/196

Workaround

Implement it yourself by producing to a dlq topic when you think you’ve retried too many times, and then don’t throw an exception so PC thinks it was successful