code: public User createUser(User user, AccessToken accessToken) {
          return getUserService().createUser(user, accessToken);
      }
docs: saves the given {@link User} to the OSIAM DB.
  
  @param user        user to be saved
  @param accessToken the OSIAM access token from for the current session
  @return the same user Object like the given but with filled metadata and a new valid id
  @throws UnauthorizedException             if the request could not be authorized.
  @throws ConflictException                 if the User could not be created
  @throws ForbiddenException                if the scope doesn't allow this request
  @throws ConnectionInitializationException if the connection to the given OSIAM service could not be initialized
  @throws IllegalStateException             if OSIAM's endpoint(s) are not properly configured