Changes:
- Deleted `schema/fleet_schema.json` (This file was previously used when
merging the osquery schema with Fleet's overrides before we switched to
using YAML override files).
- Updated the description of the `generate-merged-schema` script.
* update helper to use the osquery schema from the osquery/osquery-site repo
* update script description and generated json filename
* Add ritual to digital experience handbook
* add merged schema
* Update README.md
* Update get-extended-osquery-schema.js