Test for HTTPS support & log results.

Per request from Ryan Lane. This patch adds a JavaScript module that tests for
HTTPS support by dispatching two simultaneous and asyncronous requests (one via
HTTP, the other via HTTPS) for a pixel image on bits and then comparing the
results once both arrive. They response payload is validated by verifying the
image dimensions. A timeout ensures that hung requests are reported as
failures. A sample factor of 1:5,000 HTTP requests protects against a flood of
incoming events.

See schema at <https://meta.wikimedia.org/wiki/Schema:HttpsSupport>.

Change-Id: I7629c8be4225dbee73c0182ac18359e89769c65b