Refactor cubit api implementation

[kabaluyot]

Atm cubit APIs are located per module with tight dependency on the module "states". This means when another module wants to call an API via cubit, it needs to import the other module dependencies or create new one (introduces duplication).

Proposal:

Create a Cubit API per Repository .. Like quote_api_cubit.dart for quote_repository.dart. The API suffix helps to quickly identify API-only cubits which are stateless.