Document controlling package settings

[kibin]

This should be in docs or at least in the unfinished manual. I keep forgetting how to do that and always go to this issue to relearn. Also for others and future self all the setting names can be found in the config-schema.json file. For example.

[dvcrn]

Hey! Sorry for the late comment. I currently don't have enough free time to actively maintain this project. If you have suggestions for the manual please feel free to submit a PR with your ideas. I'd be more than happy to merge it :)

[kibin]

Okay! I will try to do this on the weekend!