Would like to delete individual pipeline runs by id [Feature Request]

**Is your feature request related to a problem? Please describe.**
I cannot delete pipeline runs from the az pipelines command set. A sample use case would be to delete all pipeline runs that are not run against the main or master branch. I often accumulate pipeline runs when testing a new or updated pipeline on a feature branch in my git repository. When I'm done I want to clean them out of the history - they have no value other than to clutter things up. I have to manually clean them one at a time in the user interface.

Would like to be able refine a query against the runs, then iterate through runs that meet certain criteria and delete them.

**Describe the solution you'd like**

az pipelines runs delete -id xxxx