Added new Constructro to logn model and started using the new constructor in UserService

Previously when creating a User we set the password and hash as blank as we had to have a user since the ID og login is the username. I created a new constructor which only takes a User as input. I feel like this is a safer way of doing it.

src/main/java/NTNU/IDATT1002/models/Login.java

@@ -25,6 +25,10 @@ public class Login {
     public Login() {
     }
 
+    public Login(User user) {
+        this.username = user.getUsername();
+    }
+
     public Login(User user, String passwordSalt , String hash) {
         this.username = user.getUsername();
         this.user = user;