Our Django settings and configuration become mess after we combine eventyay-xxx components.
Another source of confusion is that, our project is based on pretix, pretalx, which aim to be deployed as typical Linux application (with the use of directories like "/etc/", "/var").

Now we can go our way, try to make the configuration simple and neat, to help speed up development.

Objectives

• Developers and DevOps don't have to change too many configuration to make the system run.
• Support localhost-only development, localhost-only testing.
• Should be easy to change configuration to work with Docker environment.

This issue raises from #1058 attempt, should supersede it.