you would need to edit the user table and create a new column named "verified"
Set the default value of the verified column to 0
You can then add the universal email behavior to the registration page, it will still stoe the registration data into the users table
there are 2 other steps:
1) Update thew authenticate user server behavior on the login page.
On the second page of the authenticate user behavior, add another login condition, click the plus button and select the verified column, set the comparison value to "1"
2) You will need to create an administrative page where you can change a users verification status from 0 to 1