APPLIED/cmt: [unstable] linux-buildinfo support

[Seth Forshee]

On Mon, Dec 03, 2018 at 12:54:45PM +0000, Andy Whitcroft wrote:
> Add linux-buildinfo package support.  This package contains all of the
> ABI information accumulated during the build.  This means we no longer
> have to install that data onto the end-user system, and means we only 
> have to download the ABI data when doing getabis.
> 
> Pull request below.
> 
> Proposing for application to unstable.

As discussed offline, applied all patches except "[Packaging] buildinfo
-- switch getabis configuration to new package" to disco/master-next.
Thanks!