Restrict more sensitive debugging output

There are more places where sensitive information could accidentally be
disclosed.

Also, move SENSITIVE_DEBUG to config.pri so that plugins can use it.

Change-Id: Ifa4ccbd6bf4bf79412f29984c662c9e58ea01992
Reviewed-by: Kari Oikarinen <kari.oikarinen@qt.io>
Reviewed-by: Jarkko Koivikko <jarkko.koivikko@code-q.fi>
Reviewed-by: Yuntaek Rim <yuntaek.rim@myscript.com>
(cherry picked from commit 5d2d0564)