### 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
UserInfoEditView,
    UserLDAPModelView,
    UserOAuthModelView,
    UserOIDModelView,
    UserRemoteUserModelView,
    UserStatsChartView,
    ViewMenuModelView,
)
from flask_appbuilder.widgets import FormWidget
from flask_babel import lazy_gettext
from jinja2.utils import htmlsafe_json_dumps, pformat  
from pendulum.datetime import DateTime
from pendulum.parsing.exceptions import ParserError
from pygments import highlight, lexers
from pygments.formatters import HtmlFormatter
from sqlalchemy import Date, and_, desc, func, inspect, union_all
from sqlalchemy.exc import IntegrityError
from sqlalchemy.orm import joinedload
from wtforms import SelectField, validators
from wtforms.validators import InputRequired
import airflow
from airflow import models, plugins_manager, settings
from airflow.api.common.experimental.mark_tasks import (
    set_dag_run_state_to_failed,
    set_dag_run_state_to_success,
)
from airflow.compat.functools import cached_property
from airflow.configuration import AIRFLOW_CONFIG, conf
from airflow.exceptions import AirflowException
from airflow.executors.executor_loader import ExecutorLoader