update EMC analysis

DO NOT REMOVE THIS BOXED MESSAGE

Code in this merge request is subject to review by Code Owners.
The list of reviewers is posted in the comments section.
After all of the code is approved, please put a brief notice about it at the beginning of this message.

NOTE: Merging this code without getting it approved by Code Owners will result in suspending your developer rights!!!

1. Fix pi0 flow with calorimeter method
2. Unify histogram naming and filling
2. Fill V0 QA histograms even with BDT selection
3. Move all bin labels to the header, fix merging issue with TH3 with labeled bins
4. Faster event mixing
5. Updated nonlinearity function to use with cluster core energy
6. Update flow plotting macros