Add initial MC23 campaigns configuration
Add initial MC23 campaigns configuration, starting with simulation. Note as MC23a is expected to be same (or very similar) to MC21a, I already made that in CA-based config, but keeping the old pile-up setup for now. Also for MC23c we need the run number, so I will finalise pile-up in a separate MR.
While we plan to run in CA for the next production I still add legacy configurations for final testing and validation.