util: refactor util module

* refactor util exports
* early capture of prototype methods
* use template strings and args consistently

Backport-PR-URL: #14585
Backport-Reviewed-By: Anna Henningsen <anna@addaleax.net>

PR-URL: #13803
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: jasnell