**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

tests/core/test_configuration.py
"""Get Config Value from a Secret Backend"""
        mock_client = mock.MagicMock()
        
        mock_hvac.Client.return_value = mock_client
        mock_client.secrets.kv.v2.read_secret_version.return_value = Exception
        test_config = '''[test]
sql_alchemy_conn_secret = sql_alchemy_conn
'''
        test_config_default = '''[test]
sql_alchemy_conn = airflow
'''
        test_conf = AirflowConfigParser(default_config=parameterized_config(test_config_default))
        test_conf.read_string(test_config)
        test_conf.sensitive_config_values = test_conf.sensitive_config_values | {
            ('test', 'sql_alchemy_conn'),
        }
        with pytest.raises(
            AirflowConfigException,
            match=re.escape(
                'Cannot retrieve config from alternative secrets backend. '
                'Make sure it is configured properly and that the Backend '
                'is accessible.'
            ),
        ):
            test_conf.get('test', 'sql_alchemy_conn')
    def test_getboolean(self):