POULPE-503 Added the implementation of UserRegistrationResource.register()

	modified:   poulpe-view/poulpe-web-controller/src/main/java/org/jtalks/poulpe/web/controller/rest/Registration.java
	modified:   poulpe-view/poulpe-web-controller/src/main/java/org/jtalks/poulpe/web/controller/rest/User.java
	modified:   poulpe-view/poulpe-web-controller/src/main/java/org/jtalks/poulpe/web/controller/rest/UserRegistrationResource.java