WIP: Switch truth vertex type plot from histogram to profile in IDPVM

Attempts to make the plot more consistent with that shown in Figure 14 of ATL-PHYS-PUB-2019-015 by defining it as a TProfile instead of TH1.

Reco-ed mu in [40, 60] ttbar sample @ master using the following script: reco_tf_master.sh. After running IDPVM on resulting AOD, the truth type plot looks more consistent with Figure 14: (not shown here, but IVF also reconstructs less matched vertices, truth type == 0, than AMVF, as expected; however, it also reconstructs more merged vertices). However, this change still does not entirely recreate the behaviour seen in pubnote...

Tagging @npetters @vcairo @goblirsc @keli @kostyuk, let me know if this seems sensible