Modernize Diffusion lint controllers

Summary: Ref T4245. On their best day these don't work all that well, but I'm pretty sure I didn't make anything worse.

Test Plan:

• Viewed global lint.
• Viewed lint for a repository.
• Viewed lint details for a particular message.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4245

Differential Revision: https://secure.phabricator.com/D14948