Add initial resources.md for discussion

The first draft of a Kubernetes resource model.
Can we clarify where these representations apply?  I.e. are these just shorthand for use in things like UIs and CLIs or do we expect all of the various APIs to accept both forms?

For example, in JSON we can say 'memory: 1234000' or 'memory: "1234K"', but only if we explicitly go out of the way to support it as such.  Something like protobuf is less flexible.  What I don't want is for numeric types to be required to be specified as strings.  'cpu: "300"' would be terrible, since we use native ints everywhere else.

Next, I am worried that the ability to specify both SI base-10 and base-2 will be more confusing than helpful.  Many systems allow you to say "1024M" for memory but I have NEVER EVER seen that mean "1024 * 10^6" - memory is just never expressed as base-10.  But disk space is sometimes.  And network is always.

Last pedantry: Does case matter, or do we allow "k" and "K" ?