Move many "reviewers" readers to new storage

Summary:
Ref T10967.

When we query for revisions with particular reviewers, use the new table to drive the query.

When we load revisions for use in the application, also use the new table to drive the query.

This doesn't convert everything: there's some old loadRelationships() stuff still using the old table. But this moves the major stuff over.

(This also changes the icon for "commented" from a question mark to a speech bubble.)

Test Plan:

• Viewed revision lists and detail views on old and new code, saw identical outcomes.
• Updated revisions, accepted/rejected/commented on revisions.
• Hit the "Accepted Older" and "Commented Older" states by taking an action and then updating.
• Grepped for removed methods (like getEdgeData() and getDiffID()).

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10967

Differential Revision: https://secure.phabricator.com/D17517