[Component] Addressing

2 questions here : 
* We use Doctrine collections in almost all models. Should we add a direct dependency to Doctrine on each component ? Or do we let the Resource component handle that ?
* `Address` model has a dependency on `Symfony\Component\Validator\ExecutionContextInterface` via `isValidProvince`. What's the best way to handle that ? Create an `Address` entity on CoreBundle that extends `Address` from this component, and put `isValidProvince` in it ?