New VC-API architectural overview

Based on the work with both CHAPI and Supply Chain use cases, we've developed a new architectural overview, which you can find in PR #237
https://github.com/w3c-ccg/vc-api/pull/237

This is a proposal for shared language that teases out the distinctions between various implementer's perspectives, and still needs input and engagement from the larger community.

I'm sure some of the language might seem strange at first, but it seems to be a good starting point for resolving apparent differences between different use cases by baselining shared language about how the ecosystem works. 

Let's discuss.

-j

--
Joe Andrieu, PMP                                                                              joe@legreq.com
LEGENDARY REQUIREMENTS                                                        +1(805)705-8651
Do what matters.                                                                            http://legreq.com <http://www.legendaryrequirements.com/>