Add audit event for impersonated events
We added the start and end of impersonation in #315 (closed), but we should annotate any user event that is being performed while a user's being impersonated.
In audit events, an impersonated event should be attributed to the user account but note that the action was done while being impersonated by an admin.
- Record the admin who impersonated the user in each event, in addition to the impersonated user, when an admin takes an action while impersonating a user.
A simple solution may be:
User took some