Improved OAuth errors handling

As discussed @lyrixx, we now rely on the `DefaultAuthenticationFailureHandler` of Symfony which handles redirection in a clean way and as our work in `ConnectAuthenticationFailureHandler` is already handled in `AbstractAuthenticationListener` which is already extended by `ConnectAuthenticationListener`
To be able to do that we need to make `OAuthException` extends `AuthenticationException`
actually, I think you should keep this OAuthException as it is right now, and create a new exception inside ``SensioLabs\Connect\Security`` extending the Symfony one.

the ConnectAuthenticationListener would then catch the OAuthException and wrap it inside this new AuthenticationException child class