in the latest ceph releases, there are few
changes in accessing the rgw ceph dashboard
command. This commit updates the commands.
old commands
```
$ ceph dashboard set-rgw-api-access-key <access_key>
$ ceph dashboard set-rgw-api-secret-key <secret_key>
```
new commands
```
$ ceph dashboard set-rgw-api-access-key -i <file-containing-access-key>
$ ceph dashboard set-rgw-api-secret-key -i <file-containing-secret-key>
```
Signed-off-by: subhamkrai <srai@redhat.com>