R1:f8b7f0314598

Change "lint save" to not use Arcanist Projects

Summary: Ref T7604. Change `DiffusionLintSaveRunner` to use repositories instead of Arcanist Projects.

Test Plan: Ran the `save_lint.php` script and queried results using the `diffusion.getlintmessages` Conduit endpoint.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, epriestley

Maniphest Tasks: T7604

Differential Revision: https://secure.phabricator.com/D12893