Refs #4200, added more documentation to the Log class and modified default value of log_file_path config option.

Refs #4200, documented Db.php and small refactor to LogDataPurger/ReportsPurger (allow order by to be unspecified).

let the viewDataTable decide whether it can handle the view or not, better name for showAllViewsIcons

Add JsonFormat to handle json logs without regex parsing.

the viewDataTable base class should not know anything about its children. The manager should neither but it is ok until we let the actual ViewDataTables define the footer icons (thats how it should be)