**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 render_template given various input types with Native Python types"""
        with DAG("test-dag", start_date=DEFAULT_DATE, render_template_as_native_obj=True):
            task = BaseOperator(task_id="op1")
        result = task.render_template(content, context)
        assert result == expected_output
    def test_render_template_fields(self):
        """Verify if operator attributes are correctly templated."""
        task = MockOperator(task_id="op1", arg1="{{ foo }}", arg2="{{ bar }}")
        
        assert task.arg1 == "{{ foo }}"
        assert task.arg2 == "{{ bar }}"
        
        task.render_template_fields(context={"foo": "footemplated", "bar": "bartemplated"})
        assert task.arg1 == "footemplated"
        assert task.arg2 == "bartemplated"
    @pytest.mark.parametrize(("content",), [(object(),), (uuid.uuid4(),)])
    def test_render_template_fields_no_change(self, content):
        """Tests if non-templatable types remain unchanged."""
        task = BaseOperator(task_id="op1")
        result = task.render_template(content, {"foo": "bar"})
        assert content is result
    def test_nested_template_fields_declared_must_exist(self):