Enhancement: Support Multiple Measurements in a Single Configuration

[Ragansu]

Currently the configuration require one config for each type of measurements. A better alternative would be to have multiple measurements (eg: stat only and syst ) in 1 config yml.

The follwing could be the new layout for the config (all in one)

General:
      Measurement    : 
          -   Name : higgs_tautau_signal_strength_stat_only
              ParametersToFit  : 
                              - mu_htautau
              POI  : mu_htautau
          -   Name : higgs_tautau_signal_strength_float
              ParametersToFit  : 
                              - mu_htautau
                              - mu_ztautau
                              - mu_ttbar
              POI  : mu_htautau
          -   Name : higgs_tautau_signal_strength_full
              ParametersToFit  : 
                              - mu_htautau
                              - mu_ztautau
                              - mu_ttbar
                              - TES
                              - JES
              POI  : mu_htautau

RC