Summary:
add basic auditing functionalities. For the related commits for a
package, we detect the following conditions which might be suspicious to the
owners of the package:
* no revision specified
* revision not found
* author not match
* reviewedby not match
* owners not involved
* commit author not recognized
The owners of the package can change the status of the audit entries by
accepting it or specify concern.
The owner can turn on/off the auditing for a package.
Test Plan:
* verified that non-owner cannot see the details of the audit and cannot modify
it
* verified that all the audit reasons can be detected
* tested dropdown filtering and package search
* verified really normal change not detected
* verified accept/concern a commit
* tested enable/disable a package for auditing
* verified one audit applies to all <commit, packages> to the packages the
auditor owns
* verified that re-parsing a commit won't have effect if there exists a
relationship for <commit, package> already
Reviewers: epriestley, nh
Reviewed By: epriestley
CC: aran, benmathews, btrahan, mpodobnik, prithvi, TomL, epriestley
Differential Revision: 1242
