**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

tests/www/test_views.py
if username == 'test' and not self.appbuilder.sm.find_user(username='test'):
            self.appbuilder.sm.add_user(
                username='test',
                first_name='test',
                last_name='test',
                email='test@fab.org',
                role=self.appbuilder.sm.find_role('Admin'),
                password='test',
            )
        if username == 'test_user' and not self.appbuilder.sm.find_user(username='test_user'):
            self.appbuilder.sm.add_user(
                username='test_user',
                first_name='test_user',
                last_name='test_user',
                email='test_user@fab.org',
                role=self.appbuilder.sm.find_role('User'),
                password='test_user',
            )
        if username == 'test_viewer' and not self.appbuilder.sm.find_user(username='test_viewer'):
            self.appbuilder.sm.add_user(
                username='test_viewer',
                first_name='test_viewer',
                last_name='test_viewer',
                email='test_viewer@fab.org',
                role=self.appbuilder.sm.find_role('Viewer'),
                password='test_viewer',
            )
        return self.client.post('/login/', data={"username": username, "password": password})
    def logout(self):