treat bodies as of type 'value' when not described in schema

[miguelgrinberg]

It appears there are some endpoints in the schema that use a body, but do not have an explicit description of it. Example:

    {
      "availability": {
        "stack": {
          "stability": "stable",
          "visibility": "public"
        }
      },
      "description": "Puts the configuration for a geoip database to be downloaded",
      "docUrl": "https://www.elastic.co/guide/en/elasticsearch/reference/master/TODO.html",
      "name": "ingest.put_geoip_database",
      "request": null,
      "requestBodyRequired": true,
      "response": null,
      "responseMediaType": [
        "application/json"
      ],
      "stability": "stable",
      "urls": [
        {
          "methods": [
            "PUT"
          ],
          "path": "/_ingest/geoip/database/{id}"
        }
      ],
      "visibility": "public"
    },

With the current logic, the request attribute being null causes the Python and JavaScript exporters to ignore the body. With this change, these endpoints will be treated as having a body with kind == 'value', which makes the exporters output the body as a generic object.

[JoshMock]

LGTM, just a couple nits that are up to your discretion.