Determine canonical list of (run-time) dependencies for Kubernetes

We need a canonical list of official dependencies for Kubernetes, something we don't currently have. This should appear both in the docs and in the release notes.

For example, this section of the release notes is currently a grab-bag:

https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.10.md#external-dependencies

Some of those things should be listed, some shouldn't, and there's certainly stuff that ought to be listed there that isn't.

@jdumars @bgrant0607 @nickchase @zacharysarah

Start by reviewing the External Dependencies section of CHANGELOG-1.10.md and the existing Kubernetes documentation referenced by the repository. Determine which runtime dependencies are official and should be included, then document the canonical list in both the docs and release notes. Done means both locations use an agreed, complete list rather than the current grab-bag.

Written by the indexing model from the issue text.