dashboard: subj_alt_names fact refactor

the current way the variable is built results in:

```
2021-08-03 04:18:23,020 - ceph.ceph - INFO - ok: [ceph-sangadi-4x-indpt6-node1-installer] => changed=false
  ansible_facts:
    subj_alt_names: |-
      subjectAltName=ceph-sangadi-4x-indpt6-node1-installer/subjectAltName=10.0.210.223/subjectAltName=ceph-sangadi-4x-indpt6-node1-installersubjectAltName=ceph-sangadi-4x-indpt6-node2/subjectAltName=10.0.210.252/subjectAltName=ceph-sangadi-4x-indpt6-node2/
```

which is incorrect.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1978869

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit 6f1a063)

roles/ceph-dashboard/tasks/configure_dashboard.yml

@@ -61,15 +61,14 @@
           set_fact:
             subj_alt_names: >
               {% for host in groups[mgr_group_name] | default(groups[mon_group_name]) -%}
-              subjectAltName={{ hostvars[host]['ansible_facts']['hostname'] }}/subjectAltName={{ hostvars[host]['dashboard_server_addr'] }}/subjectAltName={{ hostvars[host]['ansible_facts']['fqdn'] }}
-              {%- if loop.last %}/{% endif %}
+              DNS:{{ hostvars[host]['ansible_facts']['hostname'] }},DNS:{{ hostvars[host]['ansible_facts']['fqdn'] }},IP:{{ hostvars[host]['dashboard_server_addr'] }}{% if not loop.last %},{% endif %}
               {%- endfor -%}
           run_once: true
 
         - name: generate a Self Signed OpenSSL certificate for dashboard
           shell: |
             test -f /etc/ceph/ceph-dashboard.key -a -f /etc/ceph/ceph-dashboard.crt || \
-            openssl req -new -nodes -x509 -subj '/O=IT/CN={{ dashboard_certificate_cn }}/{{ subj_alt_names | trim }}' -days 3650 -keyout /etc/ceph/ceph-dashboard.key -out /etc/ceph/ceph-dashboard.crt -extensions v3_ca
+            openssl req -new -nodes -x509 -subj '/O=IT/CN={{ dashboard_certificate_cn }}/' -addext 'subjectAltName={{ subj_alt_names | trim }}' -days 3650 -keyout /etc/ceph/ceph-dashboard.key -out /etc/ceph/ceph-dashboard.crt -extensions v3_ca
           run_once: True
 
         - name: slurp self-signed generated certificate for dashboard