R1:e117ace8c7fb

Convert Drydock lease and resource constants to strings

Summary:
Ref T9252. Drydock currently uses integer statuses, but there's no reason for this (they don't need to be ordered) and it makes debugging them, working with them, future APIs, etc., more cumbersome.

Switch to string instead.

Also rename `STATUS_OPEN` to `STATUS_ACTIVE` and `STATUS_CLOSED` to `STATUS_RELEASED` for consistency. This makes resources and leases have more similar states, and gives resource states more accurate names.

Test Plan…