Self-Signed Cert HTTPS Support for Nginx Docker Container

[HuggableShark]

Added required lines and walkthrough to explain how a user can add their own self-signed https cert and key to the docker container for increased security.

Process explained in https_README.md in fermentrack_tools/compose/production/nginx/https_README.md

[CLAassistant]

All committers have signed the CLA.

[thorrak]

Thanks for this! Excellent timing, too -- I've been looking at potentially implementing HTTPS compatibility for Fermentrack targets into TiltBridge (https://github.com/thorrak/tiltbridge/issues/215).