Enable thread-safety checking.
Fix resulting warnings.
Rework ByteStreamCnvSvc to manage slot-specific copies of event data.

The following values were implicitly set by the BS converter of the legacy EventInfo:
MCChannelNumber(0), MCEventNumber(0), MCEventWeights(std::vector<float>(1,1));
Now they are set in the BS converted of the xAOD::EventInfo too.

Fixes ATR-19871

Given the new EventInfo is an xAOD object, it requires two converters: one for the interface
object and one for the Aux store. The names of new converters are:
	EventInfoByteStreamxAODCnv
	EventInfoByteStreamAuxCnv