Homestyx hydra

R1:c6aade439283

Give Drydock leases a resourcePHID instead of a resourceID

Summary:
Ref T9252. Leases currently have a `resourceID`, but this is a bit nonstandard and generally less flexible than giving them a `resourcePHID`.

In particular, a `resourcePHID` is easier to use when rendering interfaces, since you can get handles out of a PHID.

Add a PHID column, copy over all the PHIDs that correspond to existing IDs, then drop the ID column.

Test Plan:
- Browsed web UIs.
- Inspected database during/after migration.
Repository: R1 hydra
Commit Date: Sep 24 2015