Support timeouts in OAuth1Future

Summary: Ref T13291. Ref T13285. Add "setTimeout()" to OAuth1Future to support adding timeouts to Doorkeeper OAuth requests, so we're less likely to cascade into explosive failure if a linked JIRA instance dies.

Test Plan: See next change.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13291, T13285

Differential Revision: https://secure.phabricator.com/D20529