Move task/project storage to edges

Summary: Ref T5245. This moves the actual storage over and stops reads and writes to the old table.

Test Plan:

• Verified tasks retained projects across the migration.
• Added and removed projects from tasks.
• Searched for: all, any, users' projects, not-in-projects, no-projects.

Reviewers: chad, btrahan, joshuaspence

Reviewed By: joshuaspence

Subscribers: epriestley

Maniphest Tasks: T5245

Differential Revision: https://secure.phabricator.com/D9850