style(*): add doc strings to deisctl and logger

This change quiets most `golint` warnings for the *deisctl/* and *logger/* components by adding go doc strings. It also removes several functions in the `deisctl/utils` package that were unused.

I would appreciate feedback on the accuracy and usefulness of the doc strings in particular.
What exactly is a configuration value? How do we store them and how does the cluster interact with it?

I personally like the term "platform" more than "cluster" but this is up to preference on how we want our docs' messaging to look like.