[CDG5] Notification Manager

[daniel B-J]

The NK kinda sorta supports multiple address spaces.

You can create them, delete them, add Areas to them, and set MPTasks to use them, but they still use the PMDTs as a fallback mechanism.

As it currently stands in NKv2.28, a blank address space with no Areas will still map the io memory regions and main memory (which might possibly ignore any changes made by the vm code. Not sure).

This can be overridden by placing an Area that overlaps that region, but there is currently no way to turn the feature off.