dstat: add new recipe

Dstat is a versatile replacement for vmstat, iostat, netstat and ifstat.
Dstat overcomes some of their limitations and adds some extra features,
more counters and flexibility.

Signed-off-by: Li Xin <lixin.fnst@cn.fujitsu.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>