Comment 1 for bug 1935013

I think there are two issues here:
1. charm always installs "ntp" for both bionic and focal, "ntp" is in universe with focal it should be "chrony" on focal instead
2. charm installs (and activate) ntp servers even inside LXD container.

Like ceph-mon charm, we shouldn't install ntp in LXD, but relies on baremetal.
https://bugs.launchpad.net/charm-ceph-mon/+bug/1852441
https://opendev.org/openstack/charm-ceph-mon/commit/60a9a4f27aa1cddd717431abae7a26c46f5f8bd5