IDPVM: add LRT to CA config and add new option for merged track collection

This MR adds two flags to runIDPVM.py:

1. --doLargeD0Tracks: corresponding to the existing IDPVM option doValidateLargeD0Tracks
2. --doMergedLargeD0Tracks: corresponding to a new IDPVM option doValidateMergedLargeD0Tracks, which creates a set of plots for the combined LRT+standard track collection. This is useful for computing total efficiencies, which may not be strictly additive between the two track collections

Tagging @biliu, @kkrizka