Resolve "create mini-analysis script to clean duplicate events"

Release notes

• added cafDuplicateCleaner.py which performs a miminal "analysis" using the xAOD skimming feature to remove duplicate events from data xAODs. This needs to process all data samples that might have duplicate events (typically all of one processing campaign, e.g., 2015+16, 2017, 2018) in one run in order to also be able to find (and remove) duplicates across individual files. Usage: cafDuplicateChecker.py --output dirToWriteCleanedFilesTo input1.root input2.root --- (hint: use your shell's expansion of wildcards, i.e., input*.root). For first run use additional option --checkOnly to not perform the cleaning but only check for duplicates (much faster!)
• fixed various issues regarding TQUniqueCut, mostly related to its structure being largely outdated before this revamp

Details

duplicate cleaner was tested by explicitly copying one input file (as to force duplicates to occur across file boundaries), working fine after various fixes to TQUniqueCut (for main fixes see #257 (closed))

Closes #256 (closed) and #257 (closed)