Automatic merge from submit-queue (batch tested with PRs 39092, 39126, 37380, 37093, 39237)

Improve error reporting in Ceph RBD provisioner.

- We should report an error when user references a secret that cannot be found
- We should report output of rbd create/delete commands, logging "exit code 1"
  is not enough.


Before:
```
Events:
  FirstSeen     LastSeen        Count   From                            SubobjectPath   Type            Reason                  Message
  ---------     --------        -----   ----                            -------------   --------        ------                  -------
  33m           33m             1       {persistentvolume-controller }                  Warning         ProvisioningFailed      Failed to provision volume with StorageClass "cephrbdprovisioner": rbd: create volume failed, err: exit status 1
```

After:

```
Events:
  FirstSeen     LastSeen        Count   From                            SubobjectPath   Type            Reason                  Message
  ---------     --------        -----   ----                            -------------   --------        ------                  -------
  33m           33m             1       {persistentvolume-controller }                  Warning         ProvisioningFailed      Failed to provision volume with StorageClass "cephrbdprovisioner": failed to create rbd image: exit status 1, command output: rbd: couldn't connect to the cluster
```


@rootfs, PTAL