Stack behaviour for `stacked` mode

** request *feature* **

**What is the current behavior?**

With v.10 new cool `stacked` feature, when a new toast is called it adds in front of the stack of toast, with auto close it still behaves like a queue (First in first out).

**What is the expected behavior?**

Would be nice to have a stack behavior option when using the `stacked` (Last in first out) as not all users may hover the stack and the first toast may not be seen be user before it auto closes.

Or at least some way to have access to all active toast globally, so i can manually pause those behind the first toast