Move logging, updating and testing utils into common directory

This is part of a series of PRs which add up to a substantive change.

I used '.' in import statements in some places to bring the symbols into the current namespace, to reduce the quantity of diffs in this patch.  I can do it the other way if preferred.
ah. it's golang magic.

That's awkward then. Because there can only be one such function in the package, but a) here we are in `logging.go` and b) are only initialising logging.