List Definitions

List definitions of a specific category in the revision.

POST `/revisions/:id/data/query` (Command: `list_definitions`)

Parameter	Type	Required	Description
`engine`	string	Yes	Must be `workflow_blobhub`.
`command`	string	Yes	Must be `list_definitions`.
`category`	string	Yes	`workflow` or `playground`.

Parameter	Type	Description
`definitions`	array	List of definition objects.

{
  "engine": "workflow_blobhub",
  "command": "list_definitions",
  "category": "workflow"
}

{
  "definitions": [
    {
      "id": "def_001",
      "alias": "data-process",
      "category": "workflow"
    }
  ]
}