**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
default_args = {'test_param': True, 'extra_param': True}
        dummy_class = DummyClass(default_args=default_args)
        assert dummy_class.test_param
        default_args = {'random_params': True}
        with pytest.raises(AirflowException, match='Argument.*test_param.*required'):
            DummyClass(default_args=default_args)
    def test_incorrect_priority_weight(self):
        error_msg = "`priority_weight` for task 'test_op' only accepts integers, received '<class 'str'>'."
        with pytest.raises(AirflowException, match=error_msg):
            BaseOperator(task_id="test_op", priority_weight="2")
    @pytest.mark.parametrize(
        ("content", "context", "expected_output"),
        [
            ("{{ foo }}", {"foo": "bar"}, "bar"),
            (["{{ foo }}_1", "{{ foo }}_2"], {"foo": "bar"}, ["bar_1", "bar_2"]),
            (("{{ foo }}_1", "{{ foo }}_2"), {"foo": "bar"}, ("bar_1", "bar_2")),
            (
                {"key1": "{{ foo }}_1", "key2": "{{ foo }}_2"},