Work toward being Cloud Native and support Docker

[maxbrunet]

And the same as iridakos/lofocats_api#2 for the UI:

• Add Dockerfile:
  • the container can be run as daemon (UID 2) instead of root
• Add docker-compose.yml for development:
  • Mount bind the working directory, so your changes are directly available to the container when developing
  • Use network created by docker-compose in lofocats_api, this avoids duplicating the backend stack. It could be independent but I'd recommend to use a built image of lofocats_api that was pushed to hub.docker.com.
• Accept configuration from environment variables
• Serve static assets
• Send logs to SDTOUT
• Add basic health and metrics endpoints
• Use Redis instead of the memory store, so multiple replicas can access the same cache/sessions (I also fixed the memory store config :grin:)