Add spec requires for fs sub-command.
 A few cleanups for the fs sub-command:

. Add checks for diff/cpio.
. Add missing import for rpm, when override_install_langs isn't set.
. Allow users to run some of the commands.
. Map fs snap to fssnap command.
. Add translations and add messages when you alter the filters.
. Save config. file inside the chroot.
Copy packages in/out of an installroot, for no downloads creating containers.