Added demux-ing of logging to stdout/err working around
https://github.com/sirupsen/logrus/issues/403
Turned off the default logging in favour of using hooks always.
Added fallback, if no stdout/err logger was configured, add one
automatically. This prevents unexpected lack of logging after an
upgrade in case the user's configuration file is not updated.
Fixes: https://github.com/matrix-org/dendrite/issues/2054
Signed-off-by: Martin Ashby <martin@ashbysoft.com>