port `Ntupliser` and `Objects` to C++11
As of August 2024, the code has been written mostly in C++17, with a couple of C++20 features. However, the n-tupliser and the objects must be compatible with the CMSSW version that is necessary to read the CMS data sets. Run 1 Legacy data require CMSSW 5, for which we should only assume C++11 to be available.
Furthermore, an alternative Python config file to Ntupliser_cfg.py must be provided, as Run 1 and Run 2 data are stored in different formats (also accounting for changes of Python version...).