Make util modules private

[rmorshea]

utils modules should be made private (e.g. _utils). There are some modules with the utils name that should be renamed to something like tools to indicate they are public.

[rmorshea]

I don't think this is necessary.

[Archmonger]

Closing as this is not necessary. But, similar to our other repos, we should document something along the lines of...

Anything not contained within the documentation is not considered a part of the public API and may change without notice.

So this is effectively closed in favor of #1052