Refactor all UI tests setUp method

Remove unused setUp override.
Convert calls to UI factory to API factory.
Move super setUp call to the bottom to avoid leaving the browser open.
Because tearDown method will not run if setUp raises an exception and
the API factory could raise if server does not behave as expected.
If the name should be at least 5 characters long, then it's pretty easy to adjust the entity definition. See [Host.root_pass](https://github.com/SatelliteQE/robottelo/blob/master/robottelo/entities.py#L953) for an example of how that's done.