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.
The tests in this class do reference `self.org_name` and `self.org_id`. Would it make a bit more sense to write this initialization code like this?

```python
org_attrs = entities.Organization().create()
self.org_name = org_attrs['name']
self.org_id = org_attrs['id']
```

That done, the `org_name` and `org_id` class attributes can be dropped.