LogFactory should only know ITargetWithFilterChain

[snakefoot]

• Change this method with NLog v6 to completely disconnect LogFactory from Targets/Layouts-dependency-tree
  • Remove LoggingRule-List-parameter
  • Return ITargetWithFilterChain[]

        internal TargetWithFilterChain[] BuildLoggerConfiguration(string loggerName, List<LoggingRule> loggingRules)
        {
            ...
        }

Consider extending TestTrimPublish to verify that ony using LogManager.GetCurrentClassLogger().Info("Hello") gives minimal target-file-size.