Add NEWS file

Add NEWS file

I received a request for a NEWS file. That needs to be handled by Tony
and Brian, but for now, we can at least provide one that provides a link
to github so that users who expect NEWS files from their packages will
know where to go for release information.

Reviewed-by: Neal Gompa <ngompa@datto.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #7918