Added a new task "reproducible_final_image_task".
If binary reproducibility is desired ($BUILD_REPRODUCIBLE_BINARIES" = "1"),
then recursivley modify mtimes of all files to a reproducible vale.
The value is obtained via REPRODUCIBLE_TIMESTAMP_ROOTFS.
This task is executed as the very last step in image creation, once all
the files in the image have been finalized.
[YOCTO#11176]
Signed-off-by: Juro Bystricky <juro.bystricky@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
