### Description

The stable REST API seems to be missing the functionality to delete a DAG. 
This would mirror clicking the "Trash Can" on the UI (and could maybe eventually power it)

![image](https://user-images.githubusercontent.com/80706212/131702280-2a8d0d74-6388-4b84-84c1-efabdf640cde.png)


### Use case/motivation

_No response_

### Related issues

_No response_

### 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
'action_set_retry': 'edit',
    }
    base_permissions = [
        permissions.ACTION_CAN_CREATE,
        permissions.ACTION_CAN_READ,
        permissions.ACTION_CAN_EDIT,
        permissions.ACTION_CAN_DELETE,
        permissions.ACTION_CAN_ACCESS_MENU,
    ]
    page_size = PAGE_SIZE
    list_columns = [
        'state',
        'dag_id',
        'task_id',
        'execution_date',
        'operator',
        'start_date',
        'end_date',
        'duration',
        'job_id',
        'hostname',
        'unixname',
        'priority_weight',
        'queue',
        'queued_dttm',
        'try_number',
        'pool',
        'queued_by_job_id',
        'external_executor_id',
        'log_url',