Add method to delete collection at MemoryManager level in order to use the MemoryManager EventHandler.

[VictorMuMo]

The method RemoveOutdatedCollectionAsync in the EphemeralMemoryStoreHandler class calls the method DeleteCollectionAsync from the MemoryStore class that deletes an entire collection using the name of the collection. As the method is inside the MemoryStore object the event of deleting a collection is not getting raised at the MemoryManager level and would be good to take advantage of the EventHandler that the class already has. That's what we are proposing to create a method to delete a collection at the MemoryManager level.

[fjbelizon]

I totally agree, this is a problem to be solved. The event handler managed by MemoryManager cannot know if a deletion has been made if the MemoryStore object is used directly. The correct thing to do is to have the MemoryManager object handle the deletion of collections and handle the associated event.