**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
for (source_name, config) in configs:
            for section in config.sections():
                AirflowConfigParser._replace_section_config_with_display_sources(
                    config, config_sources, display_source, raw, section, source_name
                )
    @staticmethod
    def _replace_section_config_with_display_sources(