Flatten .json files

[abovedave]

The DS structure could be simplified to match page.json files (and easy to make backwards compatible).

{
  "datasource": {
    "key": "articles",
    "source": {
      "endpoint": "1.0/site/articles"
    },
    "requestParams": [{
      "param": "slug",
      "field": "slug"
    }],
    "sort": {
      "publishedAt": -1
    },
    "paginate": true,
    "count": 15
  }
}

Could be

{
  "key": "articles",
  "source": {
    "endpoint": "1.0/site/articles"
  },
  "requestParams": [{
    "param": "slug",
    "field": "slug"
  }],
  "sort": {
    "publishedAt": -1
  },
  "paginate": true,
  "count": 15
}