`models` should not be versioned or added to the container
added a lot of useless files to .dockerignore

fix #60

Add docker-compose.yaml file

- Add ports, volumes, env_file and environment options
- Update the .gitignore to add .env file
- Access URL for the external services now uses docker-compose hostnames.
- selenium-server is now a container service dependency

Selenium is no longer directly managed by directly by hublot, but is instead an
external service dependency.
This dependency is managed in docker-compose with a selenium server image.

This simplifies a LOT of things and make the project organization cleaner.

The project now provides facilities to launch a standalone selenium server from
the project root.