Merge pull request #20100 from mogeb/iostat-plugin

mgr/iostat: implement 'ceph iostat' as a mgr plugin

Reviewed-by: John Spray <john.spray@redhat.com>
Reviewed-by: Kefu Chai <kchai@redhat.com>

diff --cc src/ceph.in
Simple merge

diff --cc src/mon/MonCommands.h
Simple merge

diff --cc src/mon/PGMap.cc
Simple merge

diff --cc src/pybind/ceph_argparse.py
Simple merge