Adds support of global configuration file if present at /config/global.yaml or /global.yaml
Add basic global.yaml file with output_dir default value of "../output".
I think it will be important later to define what goes in global.yaml and what should be removed for some configurations files on the repo (like the "output_dir" key)
Fixes #352
I think it will be important later to define what goes in global.yaml and what should be removed for some configurations files on the repo (like the "output_dir" key)