[DQM] Reimplement ECON-D packet quality flags & payload

PR description

• Replace HGCalFlaggedECONDInfoCollection → HGCalECONDPacketInfo to reimplement ECON-D packet quality flags & payload, following CMS-HGCAL/cmssw#133 & !41 (merged) by @yumiao. Note the flags are documented in DataFormats/HGCalDigi/interface/HGCalECONDPacketInfoSoA.h
• Use HGCalMappingCellIndexer::getMaxERxSize.
• Use dense module index for moduleInfo (instead of HGCalMappingCellIndexer::getTypeForModule).
• Add general .gitignore to omit output ROOT files (EDM, NANO, DQM).

Tagging @ditsiono.

PR validation

Tested with

cmsRun $CMSSW_BASE/src/HGCalCommissioning/SystemTestEventFilters/test/test_raw2reco.py charMode=0 dqmOnly=True prescale=1 maxEvents=50000 output=output_RunRUN.root inputFiles=/eos/cms/store/group/dpg_hgcal/tb_hgcal/2024/BeamTestAug/HgcalBeamtestAug2024/Relay*/Run1722785368_Link1_File0000000000.bin