[Feature] Attribute setting calls moved within class

[alicerdv]

Is your feature request related to a problem? Please describe.
Currently, some attributes of an object are set directly within the pipeline. Eg self.model.current_model = None is set in theoretical_performance method of AL pipeline

Describe the solution you'd like
Attributes like this should be methods of the class eg in the example described above, reset_current_model() should be a method in the model class

Additional context
Link to comment where this was mentioned: #33 (comment)

[thomasgaudelet]

addressed in PR #83