Add endpoint_url to boto3

[tsohst]

In the current state the script only seems only to work with AWS .. this fix seems to be able to work with other cloud vendors as well.

# Set up retry logic
retry_config = Config(
    retries={
        'max_attempts': 10,  # Number of retries
        'mode': 'standard'
    }
)

# Open server sessions
session = boto3.Session(
    aws_access_key_id=config["s3"]["key"],
    aws_secret_access_key=config["s3"]["secret"],
    region_name=config["s3"]["region"]
)

# Create an S3 resource with the endpoint URL and retry configuration
s3 = session.resource('s3',
                      endpoint_url=config["s3"]["hostname"],
                      config=retry_config)