conf.yml enhancements

[nakermann1973]

I would like to auto-generate parts of my conf.yml based on labels in other docker containers, but I have two problems.

1. I would like to have part of the config static, and part (eg a few sections) dynamic, but I can't see if any sort of include directive is supported by the yaml parted being used. Is this possible?
2. (This is docker-specific). conf.yml is placed in a directory which additionally includes app-specific assets. Using a docker volume to hold conf.yml is not possible, since this volume would also have to hold all the additional assets which are present in /app/public. Can conf.yml be used from a directory which has no additional files, so it can be placed in a docker volume shared between containers (eg the container which would be auto-generating it)