Improvements on scripts for decorrelation for cdfs

This change improves the CDF decorrelation process within higgs_dna/tools/decorrelation_CDFs_dumper/. The two previously separate scripts have been combined into a single one. Alongside the improvement of runtime, the script has been commented and more information is given in case of an error. Naming conventions have been standardized to improve consistency and there is only a minimum amount of flags needed to get to the decorrelated CDFs, e.g. by default the input variable is decorrelated against the mass.