Implemented user service with request to return the current user

Implemented user entity mapping
    - Needs refactoring

Implemented RKObjectManager configuration
    - Needs to be moved out from app delegate

Implemented AFOauth2Client configuration
    - Needs to be refatored
    - Needs to be moved out from app delegate
    - Create and integrate login flow
Created authentication service class

Refactored the code and extracted INPAuthenticationService class
Model objects implemented