Merge pull request #16460 from liewegas/wip-mgr-metadata

mon: add mgr metdata commands, and overall 'versions' command for all daemon versions

Reviewed-by: Kefu Chai <kchai@redhat.com>

diff --cc doc/release-notes.rst
Simple merge

diff --cc qa/workunits/cephtool/test.sh
Simple merge

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

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