Support for stopReadTime on KafkaIO SDF

There is already the support for startReadTime using SDF when the Kafka version is supported.

I want to add the support for stopReadTIme so we can extract messages from Kafka only up to a point in time and then the task will be finished.

One use case: when you want to only re-process (re-read) a period of time for a Kafka topic in your pipeline.