Define configuration lifecycle and management strategy

[jhpierce]

Challenge

Configuration, such as which repositories to process, at which GitHub domain, with which token, against which branch, whether or not in dry mode, with which changeset(s), needs to be cleanly loaded, and stored.

Importantly, configuration must be persisted to disk so that the pre-process step may pass information post-process step, if even execution terminates in between in the case of custom code modifications.