Do an API review

[joeduffy]

As part of getting to 1.0 for this repo, we should do an all up API review of the types and methods.

I found some of them awkward to use, such as calls like Create accepting a name string rather than the full resource URN as the provider RPC accepts. I am all for presenting a simple interface, however, I don't believe we should be lossy in doing so.

This is not the sole reason to do an API review -- we want to ensure we are happy with the interfaces overall here since we will be recommending folks use them to author providers, and won't want to break them down the road -- but this is a significant class of issue.