add storage parameter to S3FileAdmin

[samialfattani]

This PR enables users to inherit the S3Storage and inject it in S3FileAdmin

[ElLorans]

What is the advantage?

[samialfattani]

What is the advantage?

One of the uses cases that if the user wants to add the Prefix functionality, then he needs to change the behavior of some functions in S3Storage class. so this PR enables him to do so by subclassing of S3Storage and override the functions that need to bo changed to support Prefix functionality

[ElLorans]

I have never used file admin, but what happens here?

client_a = boto3.client('s3', region='us-east-1')
client_b = boto3.client('s3', region='eu-west-1')

storage = S3Storage(client_a, 'bucket-in-us')

# This is confusing - which client gets used?
admin = S3FileAdmin(client_b, 'bucket-in-eu', storage=storage)

should we rather

def __init__(
    self,
    s3_client: BaseClient | None = None,
    bucket_name: str | None = None,
    storage: S3Storage | None = None,
    *args: t.Any,
    **kwargs: t.Any,
) -> None:
    if storage is None:
        if s3_client is None or bucket_name is None:
            raise ValueError(
                "s3_client and bucket_name are required when storage is not provided"
            )
        storage = S3Storage(s3_client, bucket_name)
    elif s3_client is not None or bucket_name is not None:
        import warnings
        warnings.warn(
            "s3_client and bucket_name are ignored when storage is provided",
            UserWarning,
            stacklevel=2
        )
    
    super().__init__(*args, storage=storage, **kwargs)