Feature/update cron+darksky api

[jldeen]

• General Fixes for Docker-Compose and Cron in Docker as of Summer 2019
• Fix default timezone in container (TZ is now a build arg)
• Remove OpenWeatherMap (inconsistent temperature readings) and add support for DarkSky
• Ensure DarkSky supports geo coords for weather data
• Add a little more stout to docker logs and run first instance of poller.py outside of cron
• Update settings.ini.example to reflect DarkSky support

[gchenuet]

Thanks for this PR! :+1: