Use a POST to fetch stories

[lussoluca]

Currently, fetchStoryHtml uses a GET to fetch a story from Drupal.

For stories with a lot of props and slots values, the query string will become too long (see here).

We should convert the fetch request to a POST.

On the Drupal side, we can support both methods; if the fetch is a GET, we can retrieve the params from the query string; if it's a POST, we look in the request content.

[e0ipso]

The Drupal part is merged. This can happen now.