### Description

In Airflow UI. If we go to Browse --> DAG Runs, then DAG Runs view will be displayed.

Table contains a lot of insightful values likes DAG execution date, Start date, end date, Dag config etc

Request to add DAG duration column in the same table.
DAG Duration i.e. DAG end_date timestamp  - DAG start_date timestamp

### Use case/motivation

Analytics purpose of knowing DAG duration at all DAGs level. So that I can easily find out which DAG  have least and max duration.

### Related issues

Checked open issues. There aren't any

### 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)

airflow/www/views.py
"""Remaps UserModelView permissions to new resources and actions."""
    _class_permission_name = permissions.RESOURCE_USER
    class_permission_name_mapping = {
        'userinfoedit': permissions.RESOURCE_MY_PROFILE,
        'userinfo': permissions.RESOURCE_MY_PROFILE,
    }
    method_permission_name = {
        'userinfo': 'read',
        'download': 'read',
        'show': 'read',
        'list': 'read',
        'edit': 'edit',
        'userinfoedit': 'edit',
        'delete': 'delete',
    }
    base_permissions = [
        permissions.ACTION_CAN_READ,
        permissions.ACTION_CAN_EDIT,
        permissions.ACTION_CAN_DELETE,
    ]
    @expose("/show/<pk>", methods=["GET"])
    @has_access
    def show(self, pk):