[Feature Request] Integration with OSGi Logger

I believe that it would be very beneficial for the OSGi community to integrate Flogger with OSGi Logger the same way one can do with slf4j or Log4j. We can provide a simple OSGi Logger `BackendFactory` to take care of the OSGi integration. This will be very useful in the OSGi runtime.

If I manage, I would love to provide a PR for the integration too. Therefore, I am creating this as a reminder for the future feature request.