rgw: add rate limit for LIST & DELETE ops

rgw: add rate limit for LIST & DELETE ops

Add rate limiting specific to LIST ops,
similar to the current rate-limiting
(https://docs.ceph.com/en/latest/radosgw/admin/#rate-limit-management)

Example usage:

```
./bin/radosgw-admin ratelimit set --ratelimit-scope=user --uid=<UID> --max_list_ops=2
./bin/radosgw-admin ratelimit set --ratelimit-scope=user --uid=<UID> --max_delete_ops=2
./bin/radosgw-admin ratelimit enable --ratelimit-scope=user --uid=<UID>

./bin/radosgw-admin ratelimit get --ratelimit-scope=user --uid=<UID>
{
  "user_ratelimit": {
    "max_read_ops": 0,
    "max_write_ops": 0,
    "max_list_ops": 2,
    "max_delete_ops": 2,
    "max_read_bytes": 0,
    "max_write_bytes": 0,
    "enabled": true
  }
}

pkill -9 radosgw
./bin/radosgw -c ./ceph.conf ...

aws --endpoint-url 'http://0:8000' s3 mb s3://bkt
aws --endpoint-url 'http://0:8000' s3 cp  ./ceph.conf s3://bkt

aws --endpoint-url http://0:8000 s3api list-objects-v2 --bucket bkt --prefix 'ceph.conf' --delimiter '/'
{
    "Contents": [
        {
            "Key": "ceph.conf",
            "LastModified": "2025-07-30T13:59:38+00:00",
            "ETag": "\"13d11d431ae290134562c019d9e40c0e\"",
            "Size": 32346,
            "StorageClass": "STANDARD"
        }
    ],
    "RequestCharged": null
}

aws --endpoint-url http://0:8000 s3api list-objects-v2 --bucket bkt --prefix 'ceph.conf' --delimiter '/'
{
    "Contents": [
        {
            "Key": "ceph.conf",
            "LastModified": "2025-07-30T13:59:38+00:00",
            "ETag": "\"13d11d431ae290134562c019d9e40c0e\"",
            "Size": 32346,
            "StorageClass": "STANDARD"
        }
    ],
    "RequestCharged": null
}

aws --endpoint-url http://0:8000 s3api list-objects-v2 --bucket bkt --prefix 'ceph.conf' --delimiter '/'
argument of type 'NoneType' is not iterable

tail -F ./out/radosgw.8000.log | grep beast
...
beast: 0x7fffbbe09780:  [30/Jul/2025:15:44:50.359 +0000] " GET /bkt?list-type=2&delimiter=%2F&prefix=ceph.conf&encoding-type=url HTTP/1.1" 200 535 - "aws-cli/2.15.31 Python/3.9.21 Linux/5.14.0-570.28.1.el9_6.x86_64 source/x86_64.rhel.9 prompt/off command/s3api.list-objects-v2" - latency=0.000999995s
beast: 0x7fffbbe09780:  [30/Jul/2025:15:44:53.904 +0000] " GET /bkt?list-type=2&delimiter=%2F&prefix=ceph.conf&encoding-type=url HTTP/1.1" 200 535 - "aws-cli/2.15.31 Python/3.9.21 Linux/5.14.0-570.28.1.el9_6.x86_64 source/x86_64.rhel.9 prompt/off command/s3api.list-objects-v2" - latency=0.000999995s
                                                                                                                                           vvv
beast: 0x7fffbbe09780:  [30/Jul/2025:15:44:58.192 +0000] " GET /bkt?list-type=2&delimiter=%2F&prefix=ceph.conf&encoding-type=url HTTP/1.1" 503 228 - "aws-cli/2.15.31 Python/3.9.21 Linux/5.14.0-570.28.1.el9_6.x86_64 source/x86_64.rhel.9 prompt/off command/s3api.list-objects-v2" - latency=0.000000000s
beast: 0x7fffbbe09780:  [30/Jul/2025:15:44:58.798 +0000] " GET /bkt?list-type=2&delimiter=%2F&prefix=ceph.conf&encoding-type=url HTTP/1.1" 503 228 - "aws-cli/2.15.31 Python/3.9.21 Linux/5.14.0-570.28.1.el9_6.x86_64 source/x86_64.rhel.9 prompt/off command/s3api.list-objects-v2" - latency=0.000999994s
beast: 0x7fffbbe09780:  [30/Jul/2025:15:44:59.807 +0000] " GET /bkt?list-type=2&delimiter=%2F&prefix=ceph.conf&encoding-type=url HTTP/1.1" 503 228 - "aws-cli/2.15.31 Python/3.9.21 Linux/5.14.0-570.28.1.el9_6.x86_64 source/x86_64.rhel.9 prompt/off command/s3api.list-objects-v2" - latency=0.000000000s

s3cmd put ./ceph.conf s3://bkt/1
s3cmd put ./ceph.conf s3://bkt/2
s3cmd put ./ceph.conf s3://bkt/3

s3cmd rm s3://bkt/1
s3cmd rm s3://bkt/2
s3cmd rm s3://bkt/3

delete: 's3://bkt/1'
delete: 's3://bkt/2'
WARNING: Retrying failed request: /3 (503 (SlowDown))
WARNING: Waiting 3 sec...
WARNING: Retrying failed request: /3 (503 (SlowDown))
                                      ^^^
```

Fixes: https://tracker.ceph.com/issues/72894
Signed-off-by: Mark Kogan <mkogan@ibm.com>
Update PendingReleaseNotes

Co-authored-by: Yuval Lifshitz <yuvalif@yahoo.com>
Signed-off-by: Mark Kogan <31659604+mkogan1@users.noreply.github.com>
Update PendingReleaseNotes

Co-authored-by: Yuval Lifshitz <yuvalif@yahoo.com>
Signed-off-by: Mark Kogan <31659604+mkogan1@users.noreply.github.com>