cync2mqtt in docker configured for HASS-OS

This is very scrapily put together/MVP/alpha for https://github.com/juanboro/cync2mqtt running in a docker container/Home Assistant addon.

Currently pulls cync2mqtt via git then builds, future versions may store source within same repo.

Currently you need to generate your cync_mesh.yaml configuration outside of this addon, it currently is to go in your config directory at /config/cync2mqtt/cync_mesh.yaml. In the future I hope to implement configuration generation within the addon.