Add initial resources.md for discussion

The first draft of a Kubernetes resource model.
In that case, I'll leave it as-is.

Rationale: if somebody wants to specify a request for resources, with no hard upper bound, they can, with just one `request` stanza.  if somebody wants to specify a hard upper bound, they can, with just one `limit` stanza. The only time you need to provide both is if you explicitly want both behaviors.  I believe the defined behavior is DTRT as written ;-).

You might argue that  "nobody should be specifying limits", but I disagree - because not relying on borrowed resources is required to guarantee correct behavior in the face of resource contention.