Ga4qc

- add possibility to specify which objective a selection strategy
should use.
- implement roulette wheel selection.
- add a fitness function for the absolute distance between to unitaries.
- implement the ranking-based fitness function from Williams et al. (1998)

- add generation id parameter to multiple interfaces.
- add before generation callbacks.
- move ga parameters to a custom dataclass and add it to the
constructor of any classes that use one or more of these parameters.

- initial version.