Add script to setup development environment

[loelkes]

Title says it all.

[tg44]

Can you add the "init" part to the compose file too? https://github.com/tg44/OctoPrint-Prometheus-Exporter/blob/master/docker-compose.yml#L27
I think we can mount the plugin to the container, and also add the "default" config to it. (It is not a must, but if you are already in this thing, maybe you can do that too.)

[loelkes]

You mean there's a way to set up the octoprint container, including script and configuration, with the same ease?