Added std type to logging config. (#2060)

* Added std type to logging level.

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>

* Fix build on Windows - revert function rename SetupHookLogging

Fixes https://github.com/matrix-org/dendrite/pull/2060/files#r761692681

* Revert logging formatter changes to log.go, base.go.

The same formatting should be applied on both windows and unix, so it
makes sense to keep it in files which are shared between both platforms.

Fixes
https://github.com/matrix-org/dendrite/pull/2060#discussion_r762557679

* Remove unnecessary startup logging about info level logger.

Fixes
https://github.com/matrix-org/dendrite/pull/2060#discussion_r763959474

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

dendrite-config.yaml

@@ -370,9 +370,10 @@ tracing:
     baggage_restrictions: null
     throttler: null
 
-# Logging configuration, in addition to the standard logging that is sent to
-# stdout by Dendrite.
+# Logging configuration
 logging:
+- type: std
+  level: info
 - type: file
   level: info
   params: