Provide instructions on how to set up a certificate to use SSL through Envoy

[mofojed]

Right now if you try to access Envoy through https (eg. https://localhost.int.illumon.com:10000/iriside), you get a SSL certificate error. We should have general instructions for how to set a certificate, and then internal instructions for us to set it up using our *.int.illumon.com certs (so it works with https://localhost.int.illumon.com)

[niloc132]

The existing envoy wiring is not specifically tested to even work from the browser, ssl notwithstanding. I'm not sure we want to even suggest using the same docker-compose.yml file in this situation, since it will still end up running the now-unused websocket proxy.