Add initial resources.md for discussion

The first draft of a Kubernetes resource model.
In the name of precision, 1123 defines "host name", but 1035 defines "label" and "subdomain" with a pseudo-BNF.  We use the 1035 nomenclature everywhere else.

Second, you don't want a host name (aka label) here (which is a single token: myhost).  You want a subdomain (myhost.example.com).