Add support for packed images to wic rawcopy handler do minimize disk
usage in deploy directory and reuse of packed images between wic and
swupdate. Add `unpack` to sourceparams to unpack an bz2, gz and xz
archives.
Example:
part / --source rawcopy --sourceparams="file=core-image-minimal-qemu.ext4.gz,unpack"
Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
