R1:39ca1e7e3904

Add user.info and phid.info Conduit methods

Summary: Allow user and arbitrary object lookup by PHID.

Test Plan: Executed user.whoami, user.info, user.find and phid.info via Conduit
console.

Reviewers: jungejason, tuomaspelkonen, aran, nh

Reviewed By: nh

CC: skrul, aran, nh, jungejason, epriestley

Differential Revision: 870