Initial implementation of logging metrics for bugreport.

This change logs the following user actions:

  - Interactive bug report initiated from power menu.
  - Full bug report initiated from power menu.
  - Bug report canceled using system notification.
  - Bug report details screen open using system notification.
  - Additional Bug report screen shot taken using system notification.
  - User changed bug report name using the details screen.
  - User changed bug report title using the details screen.
  - User changed bug report description using the details screen.
  - Changes made on bug report details screen were saved by user.
  - Changes made on bug report details screen were canceled by user.

BUG: 26759986
Change-Id: I1aae98b87a4dea66a1030a024dd799b97c25dd6d