Allow to propagate errors in order to handle them acordingly.
Use playerNotifications by value to reduce the amount of allocations.
Add session managment playerNotifications.
Support marshalling notifications to plain text.

All TriggeredAction are passed in the wrapper action
DeclareTriggeredActionsAction to the controller of the triggers.
It is expected to receive an ordered list back from the user
again wrapped in a DeclareTriggeredActionsAction.
The triggered actions will be declared in from first to last.