Builds, runs very basically - useful for CI but not fully integrated
with other systems.

Additional configuration needs to be completed (analytics jobs in public
repo, and test config files in a public repo) and then travis should be
able to start using this with minimal extra configuration.

In addition to validating our supervisor and nginx configurations, this ensures we can serve static files locally as we would in production.

This service has been called discovery for a while now.

ECOM-3180

Use the committed script for Docker installation.

- Corrected WSGI package path
- Using a single database user

Updated go-agent dockerfile to override start script so container process captures the correct GO_SERVER_PORT