[DISCUSS] PIP-409: support producer configuration for retry/dead letter topic producer

[thetumbled]

Hi, Pulsar Community.
    I open a new PIP to support the producer configuration for retry/dead 
letter topic producer, which can improve the performance of retry/dead letter 
topic.
    pip link: https://github.com/apache/pulsar/pull/24022
    implementation link: https://github.com/apache/pulsar/pull/24020

Thanks,
Wenzhi Feng(thetumbled)