**Description**

It would be nice if the weight_rule default value could be managed by a global config

suggested config:
```
# Weighting method used for the effective total priority weight of the task. 
# Options are: { downstream | upstream | absolute } default is
default_weight_rule = downstream
```
**Use case / motivation**

In some pipeline, you really need to have absolute weight, and then you have to add a line in each task definition which is annoying

airflow/configuration.py
"""Get Secret Backend if defined in airflow.cfg"""
    secrets_backend_cls = conf.getimport(section='secrets', key='backend')
    if secrets_backend_cls:
        try:
            alternative_secrets_config_dict = json.loads(
                conf.get(section='secrets', key='backend_kwargs', fallback='{}')
            )
        except JSONDecodeError:
            alternative_secrets_config_dict = {}
        return secrets_backend_cls(**alternative_secrets_config_dict)
    return None
def initialize_secrets_backends() -> List[BaseSecretsBackend]:
    """
    * import secrets backend classes
    * instantiate them and return them in a list
    """
    backend_list = []
    custom_secret_backend = get_custom_secret_backend()
    if custom_secret_backend is not None:
        backend_list.append(custom_secret_backend)
    for class_name in DEFAULT_SECRETS_SEARCH_PATH:
        secrets_backend_cls = import_string(class_name)
        backend_list.append(secrets_backend_cls())
    return backend_list
@functools.lru_cache(maxsize=None)
def _DEFAULT_CONFIG():