Significant Internal Refactoring

While API for our users stays the same, loggers now behave differently on logging level configuration. Before this version, Logger. withMinimalLevel was not consistent as it didn't propagate the logging level changes through the stack of loggers. That was a cause for various funky behaviors (See #240).

Now the call to logger.withMinimalLevel(Level.Info) will cause all underlying loggers (if any) to change their minimal level as well, which should have been an expected behavior.

Those users that built custom loggers on top of internal io.odin.loggers.DefaultLogger[F[_]] would need to adjust their implementation to account for level propagation.