Provide Etherpad API key to container
Summary:
The API key will be propagated like this:
DevCentral → Zemke-Rhyne → Docker engine host → Docker Container
Ref T1419
Test Plan: Tested for pad.wolfplex.org on Equatower
Reviewers: dereckson
Reviewed By: dereckson
Maniphest Tasks: T1419
Differential Revision: http://devcentral.nasqueron.org/D1736