Making plots of kinematics

• Created a script to generate plots
• Read off output ROOT file from juggler and Plot kinematic variables
• Need to add juggler gaudirun.py with example_crystal_pion.py for digitization, reconstruction, clustering

@whit makeplot_pion.C is not currently in CI pipeline yet. At the moment, I gave a specific path to the output file from juggler. Invariant mass calculation is in it, but I think that I got wrong angle of two photons calculated. To figure out what problem I had, I will make a dataset with fixed energy and fixed momentum of pion... Not sure decay position and momentum vector or any suggestions?