smx-eip AbstractAggregator should support boolean property "reportTimeoutAsErrors"

It would be useful to add a boolean property entitled "reportTimeoutAsErrors" to the eip AbstractAggregator. The default value would be false to provide the current behavior. If set to true and a timeout occurred, an error status would be returned to all consumers.

The intent of this property is to make error handling simpler in the case where the aggregation really needs all the
exchanges to provide a valid result. This eliminates the need to implement a follow-on endpoint that compares messagesReceived to messagesExpected and throws an exception if their values differ.