Checkmk Werk 12701: Add four columns to livestatus for Robotmk

ID: 12701 Title: Add four columns to livestatus for Robotmk Component: Livestatus Level: 1 Class: New feature Version: 2.1.0i1 Add four columns to the services table in order to read Robotmk logs. The columns are LI: robotmk_last_log, the file content of the Robotmk log; LI: robotmk_last_log_gz, the gzipped file content of the Robotmk log; LI: robotmk_last_error_log, the file content of the Robotmk error log; LI: robotmk_last_error_log_gz, the gzipped file content of the Robotmk error log. The columns return the content of the files or the empty string if they are not present.