HLT Jets: Add MC20 Prerecommendations as optional HLT PFlow calib config

Purpose

Making it possible to calibrate HLT PFlow jets with the latest offline-derived recommended calibration. The calibration switch can be set via config flag, so we can run two validations with old/new config in same release. Specifically

• Adding JetEtMiss MC20 based Prerecommendations as optional HLT PFlow calibration config.
• Adding Trigger.Jet.pflowCalibKey and Trigger.Jet.emtopoCalibKey flags to set the calibKey (used in JetCalibToolsConfig.py#L23-39) directly.
• To avoid having to upload a "Trigger" version of the config file, configure the gscDepth = trackWIDTH for small-R pflow always (instead of auto).

Affects

• Adds extra Trigger.Jet config flag - removes Trigger.Jet.useTriggerCalib flag.
• Additional pflow context in JetCalibToolsConfig

Tests

• Config looks right for newly uploaded calibration config file for HLT_AntiKt4EMPFlowJets_subresjesgscIS_ftf jets :

jetrecalg_copy_HLT_AntiKt4EMPFlowJets_subresjesgscIS_ftf.jetcalib_AntiKt4EMPFlow_JREGI_TrigR22Prerec
   CalibArea = 00-04-82
   CalibSequence = JetArea_Residual_EtaJES_GSC_Insitu
   ConfigFile = PreRec_R22_PFlow_ResPU_EtaJES_GSC_February23_230215.config
   DetStore = StoreGateSvc/DetectorStore
   EventInfoKey = StoreGateSvc+EventInfo
   EvtStore = StoreGateSvc
   ExtraInputs = []
   ExtraOutputs = []
   GSCDepth = trackWIDTH
   IsData = True
   JetCollection = AntiKt4EMPFlow
   PrimaryVerticesContainerName = HLT_IDVertex_FS
   RhoKey = HLT_Kt4EMPFlowEventShape
   actualInteractionsPerCrossing = StoreGateSvc+EventInfo.actualInteractionsPerCrossing
   averageInteractionsPerCrossingKey = StoreGateSvc+EventInfo.averageInteractionsPerCrossing

(well except for JetCollection = AntiKt4EMPFlow - but it's the same for the default config. I think because it is not used to actually retrieve an xAOD collection just determine the jet reco type)

• Ran trigger count test to check nothing changes using the default config.

tagging @xingguo @mamerl @mmontell @doglioni