**Description**

Currently `BaseOperator` and `XComArgs` implements the same logic of `__lshift__`, `__rshift__` and others "chain" operations (`>>`, `<<`). It seems resonable to abstract this logic into `TaskMixin` to introduce some DRYness especially because the new concept of `TaskGroup` will also implement the same methods.

**Use case / motivation**

Limit duplication of logic.

**Related Issues**

https://github.com/apache/airflow/pull/10827#issuecomment-691927501
#10153 

airflow/models/baseoperator.py
"""@property: extra links for the task"""
        return list(set(self.operator_extra_link_dict.keys())
                    .union(self.global_operator_extra_link_dict.keys()))
    def get_extra_links(self, dttm: datetime, link_name: str) -> Optional[Dict[str, Any]]:
        """
        For an operator, gets the URL that the external links specified in
        `extra_links` should point to.
        :raise ValueError: The error message of a ValueError will be passed on through to
            the fronted to show up as a tooltip on the disabled link
        :param dttm: The datetime parsed execution date for the URL being searched for
        :param link_name: The name of the link we're looking for the URL for. Should be
            one of the options specified in `extra_links`
        :return: A URL
        """
        if link_name in self.operator_extra_link_dict:
            return self.operator_extra_link_dict[link_name].get_link(self, dttm)
        elif link_name in self.global_operator_extra_link_dict:
            return self.global_operator_extra_link_dict[link_name].get_link(self, dttm)
        else:
            return None
    @classmethod
    def get_serialized_fields(cls):