While some of the user's customizations already set in the containerfile in bootc setup, other customizations should be set in the given config for bib process.

Currently, bib searches for the config file (in toml format)  /config.toml  but a [stdin config option|https://github.com/osbuild/bootc-image-builder/pull/675] is in progress 

Goal: 

• Create the artifact with the user's customizations, at least with the filesystem