cab29d5 ui_tests: add function to run cmd on UI host

Authored and Committed by mreznik 6 years ago
    ui_tests: add function to run cmd on UI host
    
    Run shell command on the UI system using "admin"
    user's passwd from conf.
    
    https://pagure.io/freeipa/issue/7441
    
    Reviewed-By: Petr Vobornik <pvoborni@redhat.com>