Set Access-Control-Allow-Origin for Docker Registry API

Summary: Reference: https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS

Test Plan:
Tested preparing a HTML client for the microservice.

Without: Cross-Origin Request Blocked. With, request is ok.

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1908