When developing or rebuilding manifests a lot it is common to want to
checkpoint everything to the store. It seems we all have small shell
scripts hanging around for this.
Let `--checkpoint` take a shell-like glob such as `--checkpoint="*"` to
checkpoint everything.
Note that there's a behavioral change here; previously `osbuild
--checkpoint=a` would error if that specific checkpoint wasn't found.
Now `osbuild` will only error if nothing was selected by the passed
globs.
427e82e0c0