**Description**

Replace the Configuration JSON text-area with a form that has individual input fields for each key & value. This will remove the need for the user to provide a json object. See hashicorp vault's key-value secrets UI for an example of what this might look like:

![Screenshot 2020-09-21 at 12 06 03](https://user-images.githubusercontent.com/17148324/93759844-df04f680-fc02-11ea-8613-f3bcc0b22d09.png)
 
- If present these keys and values should be serialised as json client-side and posted to the trigger-dag API endpoint as the `conf` request-parameter.
- By default no conf request-parameter is sent. Perhaps a checkbox should be used to determine whether conf is sent at all?
- The user may want to add new keys, or remove keys & values that they have previously added.
- [PR-10839](https://github.com/apache/airflow/pull/10839) is pre-populating the form with the DAG's default params. The new form should be pre-populated with the keys & values from `DAG.params`


**Use case / motivation**

Currently when triggering a manual DAG run with user-provided runtime parameters, the user has to provide a correctly formatted JSON object. Filling in a form with keys & values will be a significantly better user experience, and will be less error prone & laborious than handling json in a free-text field.

This builds on the great work already done on enhancing the Trigger-DAG functionality

**Related Issues**

Originating PR: https://github.com/apache/airflow/pull/10839
"""Returns dataset dependencies graph."""
        nodes_dict: dict[str, Any] = {}
        edge_tuples: set[dict[str, str]] = set()
        for dag, dependencies in SerializedDagModel.get_dag_dependencies().items():
            dag_node_id = f"dag:{dag}"
            if dag_node_id not in nodes_dict and len(dependencies) > 0:
                for dep in dependencies:
                    if dep.dependency_type == "dag" or dep.dependency_type == "dataset":
                        nodes_dict[dag_node_id] = node_dict(dag_node_id, dag, "dag")
                        if dep.node_id not in nodes_dict:
                            nodes_dict[dep.node_id] = node_dict(
                                dep.node_id, dep.dependency_id, dep.dependency_type
                            )
                        if dep.source != "dataset":
                            edge_tuples.add((f"dag:{dep.source}", dep.node_id))
                        if dep.target != "dataset":
                            edge_tuples.add((dep.node_id, f"dag:{dep.target}"))
        nodes = list(nodes_dict.values())
        edges = [{"source": source, "target": target} for source, target in edge_tuples]
        data = {
            "nodes": nodes,
            "edges": edges,
        }
        return (
            htmlsafe_json_dumps(data, separators=(",", ":"), dumps=flask.json.dumps),
            {"Content-Type": "application/json; charset=utf-8"},
        )
    @expose("/object/datasets_summary")
    @auth.has_access([(permissions.ACTION_CAN_READ, permissions.RESOURCE_DATASET)])
    def datasets_summary(self):