Restructure Drydock so that blueprints are instances in the DB

Summary:
//(this diff used to be about applying policies to blueprints)//

This restructures Drydock so that blueprints are instances in the DB, with an associated implementation class.  Thus resources now have a `blueprintPHID` instead of `blueprintClass` and DrydockBlueprint becomes a DAO.  The old DrydockBlueprint is renamed to DrydockBlueprintImplementation, and the DrydockBlueprint DAO has a `blueprintClass` column on it.

This now just implements CAN_VIEW and CAN_EDIT policies for blueprints, although they are probably not enforced in all of the places they could be.

Test Plan: Used the `create-resource` and `lease` commands.  Closed resources and leases in the UI.  Clicked around the new and old lists to make sure everything is still working.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Maniphest Tasks: T4111, T2015

Differential Revision: https://secure.phabricator.com/D7638
Add explicit "/" when installing hooks

Summary: There's no guarantee that the local path has a trailing "/". We
should probably guarantee that at some point, but just add one
unconditionally for now.

Auditors: btrahan