Add iostat operation

[tzach]

Linux iostats reports Central Processing Unit (CPU) statistics and input/output statistics for devices, partitions and network filesystems (NFS).

It is describable to have similar functionality on osv.
Out of linux options, the following seems to be more useful:
-c Display the CPU utilization report.
-d Display the device utilization report.
-m Display statistics in megabytes per second instead of blocks or kilobytes per second. Data displayed are valid only with kernels 2.4 and later.