**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
def setUp(self):
        super().setUp()
        self.pool = {
            'pool': 'test-pool',
            'slots': 777,
            'description': 'test-pool-description',
        }
    def tearDown(self):
        self.clear_table(models.Pool)
        super().tearDown()
    def test_create_pool_with_same_name(self):
        
        resp = self.client.post('/pool/add', data=self.pool, follow_redirects=True)
        self.check_content_in_response('Added Row', resp)
        
        resp = self.client.post('/pool/add', data=self.pool, follow_redirects=True)
        self.check_content_in_response('Already exists.', resp)
    def test_create_pool_with_empty_name(self):