Add a user to an MLP level

Assigns a user to an existing MLP level. Get a username by sending the GET /users request. <br />Once you assign a user to an MLP level, you can assign a location to the user and MLP level by using the PUT /proposals/AssignLocationToMlpUser method. <br />Note: Each user can be added to only one MLP level. If a user should be assigned to another level, you first need to remove this user from the MLP level they currently belong to.