Ceph » rgw

Add support for `--bucket-id` in `radosgw-admin bucket stats` command. This will help when we know the bucket-id but not the bucket name. We do not have to run grep like this.

# radosgw-admin bucket stats | grep -B8 55c9e095-9d20-4a0f-91ef-35e786611b6f.927354.1
        "bucket": "mybucket1",
        "zonegroup": "e4460222-1aae-4c86-9c70-721cd9c13d86",
        "placement_rule": "default-placement",
        "explicit_placement": {
            "data_pool": "",
            "data_extra_pool": "",
            "index_pool": "" 
        },
        "id": "55c9e095-9d20-4a0f-91ef-35e786611b6f.927354.1",

RHBZ - https://bugzilla.redhat.com/show_bug.cgi?id=1749876