Issue #8508 : Add a maximum consume duration to the Kafka Consumer

[mattcasters]

Fixes #8508

Adds a Max consume duration (ms) option on the Kafka Consumer Batch tab so a pipeline can poll a topic for a fixed wall-clock window and then finish gracefully — even when messages keep arriving slowly enough that Stop when idle never fires.

• 0 (default) means no limit, so existing pipelines are unchanged.
• The clock starts when the transform starts. Stop when idle can still finish earlier if the topic goes quiet first.
• When a duration is set, the consumer uses short polls and wakes poll() at the deadline so an idle topic cannot block past the limit.
• GUI field, user-manual + CDC how-to updates, unit tests, and kafka IT main-0005-kafka-test-max-duration.