cephadm: change loki/promtail default image tags

cephadm: change loki/promtail default image tags

This commit changes the default images for both loki and promtail
containers.
Also, to allow this update we need to update the configuration of loki
in order to add a new storage schema configuration:

```
    - from: 2024-05-03
      store: tsdb
      object_store: filesystem
      schema: v13
      index:
        prefix: index_
        period: 24h
```

This is because 3.0.0 uses new structured metadata.

See [1][2].

[1] https://grafana.com/docs/loki/latest/operations/storage/schema/
[2] https://grafana.com/docs/loki/latest/get-started/labels/structured-metadata/#when-to-use-structured-metadata

Fixes: https://tracker.ceph.com/issues/65784
Signed-off-by: Guillaume Abrioux <gabrioux@ibm.com>