logwatch: Add new recipe

Logwatch is a customizable, pluggable log-monitoring system. It will go
through your logs for a given period of time and make a report in the areas
that you wish with the detail that you wish. Easy to use - works right out of
the package on many systems.

Signed-off-by: Qian Lei <qianl.fnst@cn.fujitsu.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>