classes/kernel: Generate reproducible kernel module tarball

If reproducible binaries are requested, generate the kernel modules
tarball in a reproducible way. Namely, sort the tarball contents, clamp
the mtime to the source date epoch, compress the archive with a
consistent compression level (9), and don't include the name and
timestamp in the compressed file.

[YOCTO #12719]

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>