**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/models/baseoperator.py
"""
        Hook that is triggered after the templated fields get replaced
        by their content. If you need your operator to alter the
        content of the file before the template is rendered,
        it should override this method to do so.
        """
    def resolve_template_files(self) -> None:
        """Getting the content of files for template_field / template_ext"""
        if self.template_ext:
            for field in self.template_fields:
                content = getattr(self, field, None)
                if content is None:
                    continue
                elif isinstance(content, str) and any(content.endswith(ext) for ext in self.template_ext):
                    env = self.get_template_env()
                    try:
                        setattr(self, field, env.loader.get_source(env, content)[0])
                    except Exception as e:
                        self.log.exception(e)
                elif isinstance(content, list):
                    env = self.dag.get_template_env()
                    for i, item in enumerate(content):
                        if isinstance(item, str) and any(item.endswith(ext) for ext in self.template_ext):
                            try:
                                content[i] = env.loader.get_source(env, item)[0]
                            except Exception as e:
                                self.log.exception(e)
        self.prepare_template()
    @property
    def upstream_list(self) -> List["BaseOperator"]: