Remove Equatable and use Freezed for the DTOs

[LezdCS]

Right now, the architecture is a mess, Equatable is used on the entities when it should be on the DTO for example.

We need to rebuild the logic following the correct implementation of the clean architecture, good example here: https://medium.com/@lennarddeurman/implementations-of-a-clean-architecture-in-flutter-projects-14b265a2de2f

Basically : rewrite the entities and DTOs

[LezdCS]

For now on develop branch : removed Equatable, cleaned the entities so there is no logic in it such as toJson and fromJson. Use of the package auto_mappr to make it easy to map my entities into the according DTO

[LezdCS]

To respect clean architecture logic, we need to remove the extends on DTOs. Once done, let's implement freezed (and json_serializable) to have clean toJson and fromJson

[LezdCS]

Also, the settings DTOs should actually be DAOs because it is LOCAL STORAGE

[LezdCS]

ok on dev branch