Cleanup dangling podman image layers to regain disk space

• 1 podman images -f dangling=true -q | xargs --no-run-if-empty podman rmi --force
  
• N Dangling image layers are usually leftovers of unfinished builds, have no references to any tagged images and serve no active purpose.
  

References

• https://stackoverflow.com/questions/45142528/what-is-a-dangling-image-and-what-is-an-unused-image
• https://docs.podman.io/en/latest/markdown/podman-images.1.html