Modernize some Harbormaster Controller/Policy infrastructure

Summary:
Ref T8095. This is just general groundwork for more exciting changes:

• Use more modern conventions around controllers, UI elements, and dialogs.
• Provide real CAN_EDIT policies and policy checks (they just don't do anything yet).

Test Plan:

• Used all affected controllers.
• Faked CAN_EDIT to POLICY_NOONE and verified everything was greyed out and unselectable.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T8095

Differential Revision: https://secure.phabricator.com/D13344