update: ensure mgrs are upgraded after ALL monitors
update: ensure mgrs are upgraded after ALL monitors

As of 1c760904b0bd1b6b0f49d6ac19d87d79f185c18f, ceph-ansible implicitly
bootstrap managers on monitors.
mgrs must be upgraded only after all monitors, therefore, this commit
refact the way mgrs are upgraded to be sure we don't upgrade a mgr
during the monitors upgrade.

This commit also ensure we handle the case were we split managers on
dedicated nodes.

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>

ceph/ceph-ansible,ceph/ceph-ansible