Port server's log sanitization to client, broker, and proxy-go
#21304 (moved) added a log sanitizer to the server (bridge) code that searches for IP addresses in logs and elides them. We noted in comment:17:ticket:21304 that the other components--client, broker, and proxy-go--can benefit from the same log sanitization.
comment:18:ticket:21304 suggests a way to do it: move the
logScrubber code into a new top-level subdirectory and
safelog package, and have the other programs