[WIP] Added PauseNodeAction

Added PauseNodeAction as a way of marking a node as being a node that causes the run to pause/suspend execution.

I think it might make sense to add a start and end time to this in case the node was not paused for the full duration of it's execution?
Ok.. will rename.

"PauseNode" as in "this node causes the run to pause".

The "Action" suffix on many of these kinda confuses me anyway since these are not performing an "action" per se :)