mgr/cephadm: customize blink_device_light cmd via j2

mgr/cephadm: customize blink_device_light cmd via j2

Customized blink a device light. By default running something like:

    lsmcli local-disk-ident-led-on --path $path

If you must, you can customize this via:

    ceph config-key set mgr/cephadm/lsmcli_blink_lights_cmd '<my jinja2 template>'

where my jinja2 template is something like:

    lsmcli local-disk-{{ ident_fault }}-led-{{'on' if on else 'off'}} --path '{{ path or dev }}'

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