FYI: I've found a solution for the Grafana Certificate. Just run the
following commands:
1.
ceph config-key set mgr/cephadm/grafana_crt -i <cert>
ceph config-key set mgr/cephadm/grafana_key -i <key>
2.
ceph orch redeploy grafana
3.
ceph config set mgr mgr/dashboard/GRAFANA_API_URL
https://ceph01.domain.tld:3000