Configure Docker Hub triggers for Docker Hub

Summary:
This is the new Docker Hub needed configuration to trigger builds,
still to be supported by keruald/dockerhub and the Notifications Center.

Ref T1814

Test Plan: Trigger a build when a commit is pushed to rNOTIF

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1814

Differential Revision: https://devcentral.nasqueron.org/D2960