Fire system action by name over multiple contentlets

Fire a default system action by name on multiple target contentlets.

Returns a list of resultant contentlet maps, each with an additional AUTO_ASSIGN_WORKFLOW property, which can be referenced by delegate services that handle automatically assigning workflow schemes to content with none.

This is the multi-contentlet variant and returns a list envelope (entity.results[]). To fire on a single contentlet, use PUT on this same path instead — it returns the single resultant contentlet map (with its identifier) directly.