Align K8s SemConv with Entities work

[ChrsMark]

A few things we'll need to work w/ Entities/Semconv group on:

(1) Should type on resource semconv have all identifying attributes or locally identifying attributes.

E.g. k8s.namespace today only contains k8s.namespace.name. How does the interact with k8s.pod type? Do I always put both when I can?

(2) Discovery of these attributes (locally and externally) (a.k.a. multi-observer problem). I'd like if each of the resources (and attributes) had some description in the markdown for how they can be discovered BOTH inside an SDK and externally (e.g. via collector).

Originally posted by @jsuereth in open-telemetry/community#2352 (comment)