Revert "CLOUDIFY-1981 avoid from saving state inside the participant. pass all needed information to the listener directly by explicitly instansiating a new instance on each task execution"

This reverts commit 8244f12d171ed8be3edf185ace3b4034e63cdc84.
CLOUDIFY-1981 fix full_task_name to be instance variable instead of class variable
Merge branch 'feature/CLOUDIFY-1981-riemann-events' into feature/CLOUDIFY-1989-event-touchups