Upgrade and cleanup of the Tau Trigger offline monitoring

This MR addresses the tau Trigger signature changes for the offline Monitoring ( ATR-27217, ATR-28611):

• Added pT threshold correction for Phase1 L1 items, used for the offline and online matching of taus when creating the L1 distributions and efficiencies: now, L1_eTAU12 will apply the correct cut of 8 GeV on the online/offline matched objects, instead of 12 GeV as before.
• Added item-specific L1Vars distributions for eTAUs, jTAUs, cTAUs, and Legacy L1 items.
• General code cleanup in the Tau monitoring (removing duplicate code, unifying nomenclature, linting, etc...)
• Unified the naming convention of some of the monitored directories: TauMon/L1 -> TauMon/L1Vars, TauMon/RNN -> TauMon/RNNVars, TauMon/EFVsTruth -> TauMon/TruthVars (for MC only).
• Updated the name of some basicVars histograms: before all were prefaced with hEF, even those in the Offline_1/3P subdirectories. The plot and axis titles were also updated.
• Added optional total efficiency histograms:
  • Disabled by default.
  • Can be enabled with --preExec 'from TrigTauMonitoring.TrigTauMonitoringConfig import TrigTauMonAlgBuilder; TrigTauMonAlgBuilder.do_total_efficiency=True'.
  • Stored in TauMon/HLT_Efficiency, and TauMon/DiTauHLT_Efficiency.
  • Moved the L1 accepted check to inside the fillHLTEfficiencies and fillDiTauHLTEfficiencies methods.
• Updated the fallback trigger list, in case the AODs don't contain the HLTMonitoring information in the Metadata.

Tagging @gipezzul, @smwang, @mashamim.