### 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', 'backfill', 'example_bash_operator'])
        with pytest.raises(AirflowException):
            dag_command.dag_backfill(cli_args)
        mock_get_dag.assert_not_called()
    def test_show_dag_print(self):
        with contextlib.redirect_stdout(io.StringIO()) as temp_stdout:
            dag_command.dag_show(self.parser.parse_args(['dags', 'show', 'example_bash_operator']))
        out = temp_stdout.getvalue()
        assert "label=example_bash_operator" in out
        assert "graph [label=example_bash_operator labelloc=t rankdir=LR]" in out
        assert "runme_2 -> run_after_loop" in out
    @mock.patch("airflow.cli.commands.dag_command.render_dag")
    def test_show_dag_dave(self, mock_render_dag):
        with contextlib.redirect_stdout(io.StringIO()) as temp_stdout:
            dag_command.dag_show(
                self.parser.parse_args(['dags', 'show', 'example_bash_operator', '--save', 'awesome.png'])
            )
        out = temp_stdout.getvalue()
        mock_render_dag.return_value.render.assert_called_once_with(
            cleanup=True, filename='awesome', format='png'
        )
        assert "File awesome.png saved" in out
    @mock.patch("airflow.cli.commands.dag_command.subprocess.Popen")
    @mock.patch("airflow.cli.commands.dag_command.render_dag")
    def test_show_dag_imgcat(self, mock_render_dag, mock_popen):