Expose the nodeId in automation context editor

In an automation chain in the context of a workflow, the nodeId variable is available but not shown in the drop-down list in the context editor.
=> show a ["nodeId"] option in the list.
=> when the option is selected, contextual help should display "Needs a workflow context. Returns the current node id. Can be used for instance in the nodeId parameter of the 'Workflow Context > Get Open Tasks' operation."