ui_tests: extend test_user suite
    
    Extend WebUI test_user suite with the following test cases:
    
    test_add_user_special
    test_user_misc
    test_ssh_keys
    test_add_delete_undo_reset
    test_disable_delete_admin
    test_login_without_username
    
    https://pagure.io/freeipa/issue/7507
    
    Reviewed-By: Petr Vobornik <pvoborni@redhat.com>