Add host and details column to instance_actions_events table

Instance action event could be a useful tool to understand and trouble
shooting the scene after invoking an API request (action) for an
instance.

This change extends the action event model by adding additional two
columns to record on which host this event took place and more detail
message for a specific event.

Implements: blueprint improve-instance-action-events
Change-Id: Id209cd7b8a3a41f86cb802d4dd681443d5717bd0
Merge "Add host and details column to instance_actions_events table"