create base email tests for activesync and add tests for outlook coverage

To address https://github.com/mozilla/gaia-ui-tests/issues/1251.

To run these tests, you will have to add the following test variables to your existing test vars file under `ActiveSync`.

```
    "Outlook":{
      "name": "",
      "email": "",
      "password": "",
      "active_sync_hostname": "",
      "active_sync_username": ""
    }
```

Add your own values. Or I can share these internally if need be.