First proof-of-principle step towards type-erased sequencer

This MR currently implements a type-erased implementation of Scheduler<..>::get_configuration and Scheduler<...>::configure_algorithms and Scheduler<...>::run

Provided this works and does not generate any (noticeable) run-time overhead, the aim is to move from a Scheduler which is templated on the sequence (and its arguments) that it schedules to a fully type-erased Scheduler which will have a constexpr templated constructor. Once this has been done it ought to address #206 (closed)