Propagator methods accepting std::list . Add some vector alternatives

The propagator methods accepting std::list , do not need a std::list to function. Could be even a vector.

Creare an internal (anonymous namespace) Impl (templated) . Added another overload with vector and used it.

ping @sroe as for the "propagator" side is not clear where std::list is really entering so one could try move these parts in plain std::vector