Adding user registration form.
Adding abstract registration form.
User registration stuff

Adding AbstractRegistrationForm along with UserRegistration form, that enables user registration. With it comes UserSearchDialog and UserSearchCallback to search for existing users or later use. Also added necessary service methods and their implementation.
User registration stuff point 2

Added userImpl which now returns all user entities from database, checks for duplicates and adds the user via user jpa controller calling Proxies.
Working push