Wip calateuth wusui

The code here can run in two ways.  For overnight tests, we do not want to bring up a browser.  In that case, we set start_browser to False.  If we set start_browser to True, then the web browser comes up.  If a yaml file specifies start_browser is True and includes an interactive task, then teuthology will sit at the interactive prompt and the user can do all sorts of stuff in the browser.  This allows one to use teuthology to set up a calamari instance in a relatively pain-free manner.