Reformulate to new Gufe Structure

[RiesBen]

check base classes and refactor them to new gufe!
General idea is, that current type annotations in Konnektor, are suboptimal. The type annotations are limiting Konnektor to RBFE-Calculations, but the implementations could in theory be used much more general! This should be indicated by using more general type anotations, as proposed currently in gufe.

This is the konnektor side issue, which is the consequence of OpenFreeEnergy/gufe#346.

[atravitz]

@RiesBen let's discuss what this entails in our meeting on Monday. Also, any details you provide here beforehand would be great!