Several updates for next UL plot iteration

• Fixes for lepton SF JSONs (that only took two months... 🙄 ): this PR is still WIP until https://gitlab.cern.ch/cms-nanoAOD/jsonpog-integration/-/merge_requests/37 is merged and the files appear on cvmfs
• b-tagging SFs: 2016 fixWP SFs are available; include full uncertainty scheme (with almost no correlations with other uncertainties at the moment, since e.g. no JES breakdown is provided: only pileup and jer are correlated)
• Add stat-group key to sample configs, to be used in the unfolding preprocessing for merging samples together (e.g. we want to have ttW, ttV and ttH merged as "ttX" in plots, but keep them separate in the fit since their theory uncertainties are decorrelated)
• Synchronize colors on plots with KIT setup (keep old colors in comments JIC, b/c I actually spent time finding a color palette)
• Fix SingleMuon/Run2018A: dataset is now v2
• Changes required because of bamboo updates: @kcormier @umolinat you'll need to update bamboo, and make sure you pip install git+https://gitlab.cern.ch/cp3-cms/CMSJMECalculators.git (I've also updated the README install instructions)
• Changes to scripts/inspectNanoFiles.py script to also check PDF weights (revealed issue with single top PDF weights)
• Changes to scripts/plotSystematicsFromOutput.py to be able to plot projections of the 2D and 3D histograms produced for the unfolding