Fix double counting of channels with K0 and charmonia for B0 decays

Summary:
Fixes issue that some of the decay of B0 to charmonia plus K0 were appearing twice, both with K0 and KS0/KL0. In these cases kept version with K0 and updated BFs close to PDG2021. To balance total BFs 4-quark configurations passed to Pythia are adjusted.

In the process adapted script to convert decay file to XML format to python3 and added two more helpers to count total BF for given particle and one to print decays of given particle containing specific daughters.

Test Plan: No specific plans for testing as no test is needed or simple enough to do at this moment.

Reviewers: tlatham, jback, abudinen

Reviewed By: tlatham, jback

Tags: #evtgen

Maniphest Tasks: T191

Differential Revision: https://phab.hepforge.org/D83