Add a command to purge old logs

[jf-viguier]

Some Prestashop log tables canb grow too much, this command could purge.

[SebSept]

Good idea.

I'm in need for this feature. With option to act on levels under a specified argument. fop:clear-log --under-level 3 : remove all logs of levels 1,2 and 3. Wording sounds not very good...

Also, as option, we can have an option like '--keep-last-24h' to avoid touching logs of the last 24h.

The command may not run without an option. --all to remove all levels, all time (except last 24h if specified)

If it's possible, it could be implemented in a way that the cleaning process can be started from a cron or a controller. new FopCleanLogCommand([1,2,3], ...)