Drop the PdtPdg.h

Drop the PdtPdg.h and use the particle names from TruthUtils instead. This is a part of efforts to consolidate all the MC- related functions and definition in TruthUtils.

Tag @jchapman @ewelina @pclark

Event/EventKernel/EventKernel/EventKernelDict.h

@@ -8,7 +8,6 @@
 #include "EventKernel/I4Momentum.h"
 #include "EventKernel/INavigable4Momentum.h"
 #include "EventKernel/IParticle.h"
-#include "EventKernel/PdtPdg.h"
 #include "EventKernel/ISignalState.h"
 #include "EventKernel/SignalStateHelper.h"
 //#include "Navigation/Navigable.h" // do we need this?