Add truth only subdetector configuration

Former-commit-id: 2c15301d90c29ae0a3b8df143604d40f3c2897e2

Simulation/SimulationJobOptions/share/subdetectors/preInclude.TruthOnlyConfig.py

+if not 'DetFlags' in dir():
+    #if you configure one detflag, you're responsible for configuring them all!
+    from AthenaCommon.DetFlags import DetFlags
+    DetFlags.all_setOff()
+DetFlags.Truth_setOn()
+DetFlags.Print()