**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/models/test_baseoperator.py
"""
        Test composition with lineage
        """
        inlet = File(url="in")
        outlet = File(url="out")
        dag = DAG("test-dag", start_date=DEFAULT_DATE)
        task1 = BaseOperator(task_id="op1", dag=dag)
        task2 = BaseOperator(task_id="op2", dag=dag)
        
        task1.supports_lineage = True
        
        inlet > task1 | (task2 > outlet)
        assert task1.get_inlet_defs() == [inlet]
        assert task2.get_inlet_defs() == [task1.task_id]
        assert task2.get_outlet_defs() == [outlet]
        fail = ClassWithCustomAttributes()
        with pytest.raises(TypeError):
            fail > task1
        with pytest.raises(TypeError):
            task1 > fail
        with pytest.raises(TypeError):
            fail | task1
        with pytest.raises(TypeError):
            task1 | fail
        task3 = BaseOperator(task_id="op3", dag=dag)
        extra = File(url="extra")
        [inlet, extra] > task3
        assert task3.get_inlet_defs() == [inlet, extra]