Automate running of cloud images with cloud-init support (for testing cloud config locally): build a cloud-init seed ISO from cloud config in seed/, create a minimal qcow2 image (backed by the original cloud image), and invoke qemu with appropriate arguments.

Usage:

$ wget https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64.img
$ ./runvm.sh ./focal-server-cloudimg-amd64.img