* Redact URLs before logging or returning in error
This does not affect strings which failed to parse, and in such a scenario
there's a mix of "which evil" to accept; we can't sanely find what should be
redacted in those cases, so we leave them alone for debugging.
The JWT library returns some errors for Operator URLs, but it rejects URLs
which contain userinfo, so there can't be passwords in those and they're safe.
Fixes#2597
* Test the URL redaction auxiliary functions
* End-to-end tests for secrets in debug/trace
Create internal/testhelper and move DummyLogger there, so it can be used from
the test/ sub-dir too.
Let DummyLogger optionally accumulate all log messages, not just retain the
last-seen message.
Confirm no passwords logged by TestLeafNodeBasicAuthFailover.
Change TestNoPasswordsFromConnectTrace to check all trace messages, not just the
most recent.
Validate existing trace redaction in TestRouteToSelf.
* Test for password in solicited route reconnect debug
