Fill missing reply permissions

Introducing user service.
- Stores persona.
- Handles building/destroying Permissions and Auth plugins (moved from AppController)
- Privacy directive uses it.

Fix #1759
The replies permissions were not filled, only the reading permissions
because privacy directive used to fill the rest. But a change made it not to touch the permissions of an annotation which has the permissions already set.


I don't think so.

Don't worry about any of that with the `auth` service. Make it dead simple. We can just put `$scope.auth = auth` in the `AppController` (instead of `auth.persona`) and then `$scope.$watch 'auth.persona', reset`. No need for promises.