This introduces a workflow to automatically close issues with the label
`status: needs information` after a number of days of inactivity.
This work has been done manually for a number of years, but I think it is safe
to close issues with this label automatically.
Not tested yet, but it is in `debug-only` mode so we can watch what it does before
deciding to turn it on (however it needs to be in `main` for it to run).