log filtering improvements

[justcoon]

current version of ZLogger (zio 2.0.2) and also other loggers implementations, in general, they are supporting just log filtering by LogLevel (Zlogger.filterLogLevel)

in general log backends implementations like logback, log4j also supporting by configuration "filtering" by package/Logger name

we should have support for something like that also in ZLogger,

previous version of zio-logging for zio 1 had LogFilter implementation, which allowed such filtering