New library datamodel

[jschlyter]

I'm working on refactoring the pypolestar library to use native Python dataclasses as the main data model. The goal is to expose only these models and hide the GraphQL representation. It will still be possible to perform raw GraphQL queries when needed as well as the latest data from a specific operation.

Work in progress at https://github.com/pypolestar/polestar_api/blob/518d0691f239e92d6049641822a2ed7eb999238f/custom_components/polestar_api/pypolestar/models.py for those interested.