Generate Subtasks on command when a parent issue contains checkboxes

[jcandan]

Like mentioned here, Trello easily converts checklist items to cards.

When planning tasks for a User Story, I often bullet point out the tasks that need to be completed. I may submit the parent task User Story while it is being groomed, so it should not generate the subtasks on submit. Eventually, I have determined the list of tasks that need to be generated, and would like to be able to issue a command to actually generate the subtasks.

Add a workflow to /js/generating-new-issues/ that accepts a command, and generates subtasks from the list of checkboxes in the description.