vmctl(8): Add 'vmctl status -r'

vmctl(8): Add 'vmctl status -r'

The -r option can be used to limit the output of 'vmctl status' to only
running VMs. This is useful for machines that have a large number of
stopped VMs, as the running ones are printed at the top by default and
previously required scrolling back to see the list of running VMs, and/or
using 'grep RUNNING'.

There is no change for users not using -r.

ok dv