Ability to delete workflows by ID

**Is your feature request related to a problem? Please describe.**
I would like to be able to delete a workflow using its ID. I know that a lot of the providers provide some automated cleanup but not all. Also in my case I have a parent workflow but can create up to 4 million quick running child workflows. 90% of the child workflows will auto complete in seconds but the rest will be long running. When a child workflow completes in a parent process or somehow in the workflow it self i would like to set it to be deleted from the database once it completes sucessfully. My plan was to write code to delete it based on its ID but i realised the IPersistance interface has no delete methods.

**Describe the solution you'd like**
Delete workflow by ID added to the IPersistance or potentially a setting on a workflow itself to state to auto delete it on completion if sucessful

**Describe alternatives you've considered**
Creating a new interface and extending the persistance classes but does nto seem like the best solution