Make RouDi Startup Parameters available in TOML Config

## Brief description
Currently there are parameters passed in different ways to RouDi:
- as command line option in roudi_cmd_line_parser.cpp
- as struct RoudiStartupParameters passed to the roudi ctor in roudi.hpp
- segment/mempool config as C++ API in RouDiConfig available for roudi_main.cpp or serialized in the TOML file

We need to wrap up the existing parameters and give the end-user a standardized way to pass them to RouDi. Possible solution would be to move some parameters to the TOML file.

- [ ] define where to pass startup parameters to RouDi
- [ ] optional: move chosen parameters from struct RoudiStartupParameters to TOML config
- [ ] document for the end-user the possible parameter sets and give example how to use them