addresses #2422
- creates settings user controller
- creates user model object
- updates user fixture to be compatible with user model
- updates settings/user template
- add validator to Ember Admin
- use validator to validate user model is valid
- add mock response to /users/me/ path
- creates models/base file for all models to inherit from
- add mock response to /ghost/changepw/ path
* Adding **user fixtures** for signin
* Adds an initializer for the **current logged in user**.
The created singleton object is injected into all controllers + routes.
It can be used inside routes + controllers with this.get('user').
For simple development the object is instanciated with a userFixture.
Once a proper login and api mock is in place, the fixture needs to be removed.
* Added **route 'login'** on url '/ghost/ember/signin'
* Added authenticated route with an error hook that redirects to the login route, if status 401 (unauthorized) is returned from REST API.
* All "secure" routes now extend from authenticated route
* Add /ghost/ember to noAuthNeeded routes in middleware
