Define and agree upon design goals

[wyc]

We need to specify design goals, and/or design and decision criteria, for Identity Hubs. These should comprehensively describe what is in or (more importantly) out of scope for Identity Hubs, and roughly how the in-scope items are organized.

I hope to make progress on the working group calls--this should certainly be a group decision, but I will self-assign to make sure someone is driving it forward.

Closes #60

[TallTed]

I don't quite understand how this solves the problem of this repo's README being useless (as it is entirely empty)... But maybe you're thinking updating the README is implicit in the above? I suggest making all implicit expectations explicit.

[csuwildcat]

We did this as a matter of course for the general scope of the SDS WG, initially in the joint Hub/EDV group. Closing now, as this is something we can pull in from there as an appendix item.