**Description**
In the trigger page, there is a text area to enter (optional) conf json. It would be great if a sample JSON can be provided programatically while defining DAG

**Use case / motivation**

This will improve usability of the UI that triggers a DAG

airflow/www/views.py
"""Set state to 'failed'"""
        self.set_task_instance_state(tis, State.FAILED)
        self.update_redirect()
        return redirect(self.get_redirect())
    @action('set_success', "Set state to 'success'", '', single=False)
    @auth.has_access(
        [
            (permissions.ACTION_CAN_EDIT, permissions.RESOURCE_DAG),
        ]
    )
    def action_set_success(self, tis):
        """Set state to 'success'"""
        self.set_task_instance_state(tis, State.SUCCESS)
        self.update_redirect()
        return redirect(self.get_redirect())
    @action('set_retry', "Set state to 'up_for_retry'", '', single=False)
    @auth.has_access(
        [
            (permissions.ACTION_CAN_EDIT, permissions.RESOURCE_DAG),
        ]
    )
    def action_set_retry(self, tis):