package/libblockdev: new package

libblockdev is a C library supporting GObject introspection for
manipulation of block devices. It has a plugin-based architecture
where each technology (like LVM, Btrfs, MD RAID, Swap,...) is
implemented in a separate plugin, possibly with multiple
implementations.

gobject-introspection is not a strict dependency and may be disabled
via a configure flag.

This is the base package with everything disabled, the subsequent
patches in this series will add more options necessary to bump udisks
to the latest.

Signed-off-by: Adam Duskett <Aduskett@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>