R1:dfdbe7a6be04

Allow "bin/drydock lease ..." to select particular blueprints with "--blueprint"

Summary: Ref T13676. See discussion in that task.

Test Plan: Tried nonsense blueprint identifiers, duplicate identifiers, incompatible identifiers, and valid identifiers. Got apparently sensible behavior in all cases.

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T13676

Differential Revision: https://secure.phabricator.com/D21802