Interfaces are package private their implementations are not

[Lacritz]

Hi Folks,

I have noticed that the UsersService interface is package private while the implementation is not. This leads to an unintuitive API.
The entry point for all of the identity services (UsersService, GroupsService) are the IdentityService interface and the regarding implementation IdentityServiceImpl.

To be more convenient - you should either make GroupsServiceImpl and UsersServiceImpl package private or the regarding interfaces public.

Please verify - I would add a pull requests with the changes necessary.