[WFLY-2637] Only allow log files defined in known file handlers to be listed and read

Changes the ```list-log-files``` and ```read-log-file``` operations to only allow log files found in a ```file-handler```, ```periodic-rotating-file-handler``` and ```size-rotating-file-handler```. This eliminates the need to filter out files from an audit log configuration or the operations being used as a generic file viewer.