Add tutorial notebook for offline estimation

[WardLT]

Describe how to build then use an offline estimator, describing the different kinds of loss functions available.

Expand what's already in here: https://github.com/ROVI-org/auto-soh/blob/main/notebooks/state-estimation-for-camp-cell.ipynb

[WardLT]

Perhaps phrase the notebook around generating initial guesses for online estimation through a combination of extractors and offline estimation