Merge in games-on-k8s/docker-factorio gen_config

[deefdragon]

games-on-k8s/docker-factorio has been effectively abandoned, but has gen_config.py, which is very powerful for the creation of the server-settings.json file. Addition of gen_config would allow for one line server launches (as opposed to starting, stoping, editing the config, and restarting), much easier kubernetes integration, and much easier public hosting of games.

License is also MIT.

I would be willing to do the merge, testing, and PR if the addition of gen_config.py is acceptable.

[SuperSandro2000]

I don't really want to add python just for generating the config.

[deefdragon]

Just checked, and you do have busybox sed in the container. I would be willing to write a bash script that took a template and replaced all the values with either defaults, or the environment parameters. Only additions then would be the template and new script.

It would not take much to actually expand the script to any other configs that the user may want to edit.

[SuperSandro2000]

We can also add the standalone sed cause compared to full blown python it is tiny.
I would merge it if it is error proof (eg missing variables) and maintainable.

[deefdragon]

Moved to PR #304

[jonfairbanks]

This would be an awesome addition, thanks for taking this on.