Modules fullname feature

Added ability to specify in suite configs full helpers classes, for example:

```yaml
class_name: CodeGuy
modules:
    enabled:
      - CodeHelper
      - common\tests\_helpers\FixtureHelper
```

This is very useful when you separated your tests per application tier and dont want to copy-paste helpers and modules. For example we use it in `yii2-advanced` where application is separated on `backend`, `common`, `console`, `frontend`.