An RFC to standarize on two workflows

This RFC proposes two workflows as "supported", and abstracts
as much of their differences as possible through the use of
additional generators and functionality in the 'chef' command.

If accepted, this RFC would also serve as a guide for tool makers,
as to what the requirements are for maximum converage in the Chef
community.

While other workflows are possible, this RFCs job is to say which
ones we support officially.
I prefer JSON as the default because I am them more confident that the item I am uploading to the server is the same as the item I have on disk.  However, if knife-diff and other tools were to learn about the the Ruby DSL and handle it well, I wouldn't care as much.

That being said, I think a prerequisite to defaulting to Ruby is that we support Ruby for all policy types.  Currently data bag items do not have a Ruby format as far as I know.  To me, the default repo setup should present a user with a consistent experience when editing policy artifacts.