Update ICounterSummarySvc to use the new Counters
Gaudi's ICounterSummarySvc and its implementations, specifically LHCb's XMLSummarySvc, need to be updated to correctly transform data from the new counters. The current implementation is based on the obsolete StatEntity class, which restricts its applicability.
The problem is similar to the transformation for streaming and messaging services. The different information and representations of information encoded by the different counter classes need to be expressed in an XML format.
One general way to solve this problem is to extend the PrintableCounter base class with functions intended produce appropriately formatted XML blocks.