[IMPROVEMENT]: Migrate to basic models from freezed

[wizlif]

Freezed is taking a whole lot of building time.

However we do not really have to use it for the models so we are opting to use plain dart classes with equatable.

[pythonhubdev]

But as you have suggested this before https://codewithandrea.com/tips/speed-up-code-generation-build-runner-dart-flutter/ can we try this once?

[wizlif]

Would be interesting to see