add CollectorSink for AggregatedTraces

add a CollectorSink in the TraceAggregationComposite which is accessible via a getter-Method in the Configuration

like the inital Version in commit 60a2b084

I think the collector sinks should be part of the configuration not of the composites, because it is not needed in other configurations that use this composite.

So this would be part of #33

Status changed to closed