### Description

Recently, we added [a new DAG dependencies view](https://github.com/apache/airflow/pull/13199) to the webserver. It would be helpful if a similar diagram could also be displayed/generated using the CLI. For now, only [one DAG can be displayed](http://airflow.apache.org/docs/apache-airflow/stable/usage-cli.html#exporting-dag-structure-as-an-image) using CLI.
![image](https://user-images.githubusercontent.com/12058428/137945580-6a33f919-2648-4980-bd2c-b40cfcacc9fe.png)

If anyone is interested, I will be happy to help with the review.

### Use case/motivation

* Keep parity between CLI and web serwer.
* Enable the writing of scripts that use these diagrams, e.g. for attaching in the documentation.

### Related issues

https://github.com/apache/airflow/pull/13199/files

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

tests/cli/commands/test_dag_command.py
cli_args = self.parser.parse_args(['dags', 'test', 'example_bash_operator', DEFAULT_DATE.isoformat()])
        dag_command.dag_test(cli_args)
        mock_get_dag.assert_has_calls(
            [
                mock.call(subdir=cli_args.subdir, dag_id='example_bash_operator'),
                mock.call().clear(
                    start_date=cli_args.execution_date,
                    end_date=cli_args.execution_date,
                    dag_run_state=State.NONE,
                ),
                mock.call().run(
                    executor=mock_executor.return_value,
                    start_date=cli_args.execution_date,
                    end_date=cli_args.execution_date,
                    run_at_least_once=True,
                ),
            ]
        )
    @mock.patch("airflow.cli.commands.dag_command.render_dag", return_value=MagicMock(source="SOURCE"))
    @mock.patch("airflow.cli.commands.dag_command.DebugExecutor")
    @mock.patch("airflow.cli.commands.dag_command.get_dag")
    def test_dag_test_show_dag(self, mock_get_dag, mock_executor, mock_render_dag):