Move BlameController away from ancient "TABLE_COMMIT"

Summary:
Ref T13276. Differential has a pre-edge "TABLE_COMMIT" with about a half-dozen weird callers I'd like to get rid of.

Move blame to use edges instead. (Bonus: this makes blame respect edge edits in the UI.)

Since there are some more callers to clean up this code may move into some "RelatedObjectQueryThing" class or something, but I'm taking it one step at a time for now.

Test Plan:

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13276

Differential Revision: https://secure.phabricator.com/D20457