Clean up completed jobs at some point

[Lnaden]

Completed tasks sit on the server as complete. It may be worth to set a task to regularly delete the completed tasks if they havent been accessed in a while.

This would be to avoid bloating the server up with lingering files.

It may be worth exposing a delete entry (can technically be done now if you can compute the hash, but codifying it might be better than just an exposed entpoint)