Add action logic to be able to optionally undo its changes

Add to the action/tasks framework a notion of undoing a Task, and the underlying work/changes an action did.

This would be optional, and unless all actions in a given task have undo functionality, you cannot undo a task.

This would allow us to make all core actions and tasks be able to undo themselves, and allow us the option of explicitly marking some actions that cannot be undone safely.

Could be added without breaking backwards compatibility and allow us to add undo functionality to existing actions over time.