gptfdisk: Add host package

This tool which is useful for scripts that create flash images with
multiple partitions.  The host-parted package can do this too, but is
missing a number of features that the gptfdisk program has for dealing
with GPT.

The interactive gdisk and curses based sgdisk aren't built.  Just the
scriptable tool sgdisk.  The target package allows configuring which
tools are built, but this seem unnecessarily complex for the host
tool.

[Thomas: minor reformatting tweaks.]

Signed-off-by: Trent Piepho <tpiepho@kymetacorp.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>