Is it possible to add YAML.FILE as a Value token?

Hi,

The stepFile feature allows the user to reference a step written in json format.

```
stepFile: "${JSON.FILE:reusable_content/get_authorisation.json}"
```

In our usage we are writing scenarion in yaml format - but it appears that the stepFile only supports json. Is there any plan to support a YAML file value token similar to JSON.FILE?

Support for ZIP would also be something that be useful for test cases we are currently attempting to implement.