qa/cephadm: Add yaml output to smoke test

this will provide a more detailed output, like

```yaml
...snip...
service_type: node-exporter
service_name: node-exporter
placement:
  host_pattern: '*'
status:
  created: '2021-01-18T11:21:56.024810Z'
  last_refresh: '2021-01-18T11:23:24.477672Z'
  running: 0
  size: 1
events:
- "2021-01-18T11:23:09.602644Z service:node-exporter [ERROR] \"Failed while placing\
  \ node-exporter.ubuntuon ubuntu: cephadm exited with an error code: 1, stderr:Deploy\
  \ daemon node-exporter.ubuntu ...\nVerifying port 9100 ...\nTraceback (most recent\
  \ call last):\n  File \"<stdin>\", line 7274, in <module>\n  File \"<stdin>\", line\
  \ 1563, in _default_image\n  File \"<stdin>\", line 3698, in command_deploy\n  File\
  \ \"<stdin>\", line 2338, in deploy_daemon\n  File \"<stdin>\", line 1961, in create_daemon_dirs\n\
  AssertionError\""
...snip...
```

Signed-off-by: Sebastian Wagner <sebastian.wagner@suse.com>

qa/suites/rados/cephadm/smoke/start.yaml

@@ -11,3 +11,4 @@ tasks:
       - ceph orch ls
       - ceph orch host ls
       - ceph orch device ls
+      - ceph orch ls --format yaml