[Refactor] Optimize storage models

[i5hi]

Regarding the long overdue refactor of the models and storage classes.

Thanks @saiy2k for putting this slideshow together!

https://docs.google.com/presentation/d/1VMN7MrgU9wXPgOSJjCKiFkKN7eMdfCe2PMhClawcJlI/edit#slide=id.p

This covers the core idea behind this refactor. It is absolutely necessary at this stage because we don't want to keep adding more technical debt by adapting all these new features into the old architecture.

This should be a comprehensive refactor and should not require such a major refactor again.

[i5hi]

This issue is exclusively for model and pkg. Bloc updates can happen later as a separate issue.