Update a few things in Drydock for policies

Summary: DrydockResource has been updated to be policy-aware (although there are no policy columns).

Test Plan: Clicked around in Drydock, viewed resources and leases, everything still seemed to work.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Maniphest Tasks: T3605, T4111

Differential Revision: https://secure.phabricator.com/D7595