Distinguish between FitResult and ParameterConfiguration? #562
Description
The FitResults object can be passed into various model_utils pieces and can also be modified to e.g. obtain predictions for varied parameter configurations. In those cases the name no longer makes sense. It may be a good idea to have a more generic ParameterConfiguration (or similar) object, with FitResults being a special case.
More functionality could then also be added to ParameterConfiguration to help with modifications. Related to this, a configuration object could even serve as input to configure an MLE with some convenience functions like changing parameters by name in a dict.