New plot to monitor alignment weak modes added to ParticleMassMonitor

Some updates to the ParticleMassMonitor:

• Addition of a new profile histogram showing the difference between the average of the reconstructed mass distribution and the central value of the mass histogram in bins of the momentum difference between the positively and negatively charged daughters. Useful to monitor the curvature bias effect on alignment
• Generalisation of the monitor to remove the hard-coded particle decays to solve the issue: #506 (closed)

Goes with Moore!2818 (merged) and Alignment!436 (merged)