swap "Add" and "Cancel" button ordering for access management
    
    Prior to this change, the "Cancel" button was much too close to the
    place where users click to select an access level. This made it too easy
    for users to accidentally click the "Cancel" button after quickly
    clicking on all the other interface choices.
    
    Move the "Add" button to the left so that it is directly below the
    dropdown input field.
    
    Merges https://pagure.io/pagure/pull-request/4665