Proposal: Config file model for Galley

Hi,

I’ve been working on a new file based config model for Galley. This is for dealing with the over-expanding command-line flags that we need to deal with. Here is a document explaining how it looks like
https://docs.google.com/document/d/12f6ibB65qyPMLVC5yIclF97NAHiB2BHM7M0GKlmN5Qc/edit#

PTAL and comment.

Thanks