Expose option to enable `error_on_callbacks` in `KafkaProducer.send`

With `Future.error_on_callbacks == False`, the default, errors raised in callbacks are suppressed (even critical ones like `MemoryError`). The only feasible way to change this behavior is currently to override the class attribute, but this has global effects and might not be possible in a large application with multiple usages and different needs. I'm proposing to change this class attribute to an instance attribute, and expose a way to change its value, either through instantiation of `KafkaProducer`, or by passing a parameter to `.send()`.