DAOD_TRIG prototype for Run 3

Starting with copying PHYS.py to TRIG.py and enabling storing trigger containers. Adding some first trigger collections from Run 3 EDM: new navigation, b-jet, and B-tagging containers (via smart slimming list).

Checked using an AOD file produced in master with Run 3 trigger from /eos/atlas/atlascerngroupdisk/data-art/build-output/master/Athena/x86_64-centos7-gcc8-opt/2020-09-21T2101/TrigAnalysisTest/test_trigAna_RDOtoAOD_v1Dev_build/AOD.pool.root

and running the transform

Reco_tf.py --inputAODFile AOD.pool.root --outputDAODFile art.pool.root --reductionConf TRIG  --preExec "from AthenaCommon.DetFlags import DetFlags;DetFlags.detdescr.all_setOff(); DetFlags.BField_setOn(); from AthenaCommon.AlgSequence import AlgSequence;topSequence = AlgSequence ();topSequence += CfgMgr.xAODMaker__DynVarFixerAlg(\"BTaggingELFixer\", Containers = [\"BTagging_AntiKt4EMTopoAux.\" ] )" --postExec "from AthenaCommon.AppMgr import ServiceMgr;ServiceMgr.MessageSvc.defaultLimit=0;ServiceMgr.MessageSvc.debugLimit=0" --debug

In this test, the trigger navigation, b-jets and B-tagging containers are stored in the output DAOD.
Tagging @dguest for planning the DAOD production for b-jet trigger optimization.
Tagging @jburr as this is potentially related to trigger for analyses (including trigger containers for matching to offline).