* Use parent_id to find cause of events with new contexts
When looking up the causing event for logbook display, use the `parent_id`
of the current context if the current context just points back to the
current event.
This now shows in the logbook the cause of an event in the case that a
component has created a new context from an existing context and tied
them together via the `Context.parent_id`.
* Fix exception when parent event not available
* Use async_Log_entry to avoid jump into executor
e35e460e69