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